Terminate with extreme prejudice

Hours after nightfall, when the last lights are going out and the only sound is the rustle of the pines and sweet gums on the balmy Georgia wind, the terror that enveloped Wynnton seems closer, more palpable. I'd planned to take a slow drive, to pause and stare at these moon-shadowed dwellings as once the killer saw them, in the moments before he pounced. But my guide, a local architectural historian, seemed reluctant to linger. 'People might not like it,' she said. 'You don't want to have to explain yourself to the police. Besides, a lot of folks here have guns.'

If one knew nothing of its history, Wynnton after dark might feel no different from any American suburb. But knowledge cannot be undone, and despite myself I shared her unease. I had seen the crime scene photographs. It wasn't just the bodies, their swollen faces seeming to betray a heart-rending mix of fear and resignation. What conveyed the sense of violation most was the ordinariness of their surroundings. In one home, the story of a death struggle was told by books, some still stacked neatly on their shelves, others strewn across a patterned carpet; in another, undergarments had been scattered on the floor, by a murderer looking for a weapon. Family photographs seemed to gaze down at the victims: twisted, bruised, exposed.

For eight months, from September 1977 to April 1978, Wynnton, a rich and desirable neighbourhood of Columbus, Georgia, a city of 200,000 people located 100 miles south of Atlanta, lay at the mercy of a serial killer. His seven victims were all raped or sexually assaulted, then strangled, most with ligatures fashioned from their underwear. They were all white, mostly wealthy, elderly women who lived alone, and he, the police believed, was an African-American. Less than a decade after the assassination of Martin Luther King, with many civil rights issues still to settle, this was not an unimportant detail in Georgia.

The strangler seemed to be able to strike at will. For months, Wynnton was flooded, night and day, by police officers, state troopers, freelance vigilantes and patrols by the Ku Klux Klan, while those deemed possible victims were given hotlines and panic buttons. None of it made any difference. By the time the murderer ceased his rampage in April 1978, apparently of his own volition, the police were consulting psychics, and speaking to the media of trying to catch a 'will o' the wisp, a ghost'.

Today that ghost has a name: Carlton Michael Gary. Arrested for the murders in May 1984, more than six years after the final killing, he was convicted and sentenced to death in the summer of 1986. Having always protested his innocence, he is now fighting his last appeal. There's a lot riding on Gary's case. Columbus's legal establishment is almost entirely white, and it has a tough record. A report by the Southern Center for Human Rights in Atlanta dubbed the city 'the buckle of the death belt', finding that its courts had sent more prisoners to death row since the Supreme Court reinstated capital punishment in 1976 than anywhere else in Georgia. For many years, most of the judges who sit on the bench of Columbus's Superior Court have been recruited from the ranks of prosecutors in the district attorney's office, and any candidates unwise enough to reveal misgivings about capital punishment have been voted out of office.

Yet there are people in Columbus, not all of them black, who still have doubts about the stranglings case. Some point to Carlton Gary's personality: extrovert, flamboyant, and unusually attractive to women. In his autobiography, Robert Ressler, who founded the FBI's psychological profiling unit and coined the term 'serial killer', summed up the personality type he deemed invariably responsible for this type of crime: not only lonely and socially inadequate, but 'dysfunctional sexually; that is, they were unable to have and maintain mature, consensual sexual experiences with other adults... they resented not having them; it was this resentment that fuelled their aggressive, murderous behaviour.'

This was not Carlton Gary. At the time of the murders, he was appearing up to five times a night on local television, modelling in advertisements for a Columbus clothing store, the Movin' Man. He liked to spend the proceeds at a local nightclub, Floyd Washington's F&W Control Tower. 'Carlton used to come here every other night,' says Washington. 'He had many girlfriends: beautiful ones, with good jobs. The idea that he would leave this club with a girl and then leave her to go and rape an old woman - it just don't add up.'

Others point to the fact that while the prosecution spent two years and millions of dollars assembling its case, he was denied any funding at all for his defence: instead of a trial, says his one-time lawyer Gary Parker, he had a 'legal lynching'. In times past, Columbus saw its share of the illegal kind. John Land, the judge who made the funding decision, is the son of Aaron Land, who in 1912 led the lynching of a 14-year-old African-American boy accused of killing a Land cousin in a hunting accident. Now it is John Land's great-nephew, Clay Land, a former Republican state politician appointed to the bench by George W. Bush, who holds Carlton Gary's fate in his hands, as the judge in charge of his current, federal court appeal.

Ten years ago, when Gary's case was appealed unsuccessfully to the state courts, his lawyers discovered that the prosecution had concealed a large mass of evidence from his trial, which appeared to undermine much of the case against him. Now there is more fresh evidence, some of it unearthed by me, in the course of an investigation which has spanned four years. But in a procedural ruling in April 2004, Judge Land declined to consider this testimony, saying Gary should have filed it in time for earlier appeals. Unless Land changes his mind or finds some other reason for reversing Gary's convictions, the likelihood is that he will die by lethal injection some time in 2006.

On 16 September 1977, Ferne Jackson, 59, the longserving director of Columbus's health education department, failed to come to work or call in sick. Jackson was a woman of meticulous habits, and one of her colleagues went to her house on 17th street to investigate. Her killer had entered through sliding doors at the rear. Years later, at Carlton Gary's trial, Joe Webber, the medical examiner, described her injuries. The killer had tied a nylon stocking and a dressing gown cord together and wrapped them round her neck three times, leaving three 'deep crevasses'. Her breastbone had been fractured, an act which would have required the application of enormous force. Although there was no sign of sperm, Ferne Jackson had been raped. Her killer ransacked her house, but left diamonds and other valuables untouched.

Jackson's murder was barely a month after the capture of David Berkowitz, the sexually-driven 'Son of Sam' who killed or seriously injured a dozen women in New York. Eight days after the murder of Jackson it became apparent that someone similar was on the loose in Columbus.

Jean Dimenstein, the strangler's second victim, was 71, a spinster from Philadelphia who owned a small department store. She spent the evening of 24 September with two friends at a steak house. Her companions drove her home and watched from the car as she let herself into her house on 21st Street, about half a mile from the residence of Mrs Jackson. Some time later that night, the killer silently dismantled the mountings of her garage door - an operation said to have taken up to three hours - and entered Dimenstein's house. When her sister-in-law arrived there at 10am the next day she saw the open doorway, and called the police.

Like Jackson, Dimenstein was beaten about the head, strangled with a stocking wrapped around her neck three times, and raped, and this time, the killer did ejaculate. Again, it appeared that the killer had stolen nothing. The Mayor of Columbus, Jack Mickle, addressed reporters on her lawn, ringed by 10 police cars. 'We've got a maniac,' he said. 'We gotta get this guy.' All police leave was cancelled. Staff on administrative duties were moved to the streets to join new, intensive patrols.

Curtis McClung, Columbus's police chief, had been in his post just a year. Possessed of a degree in police sciences, he was determined to be seen as a new model police chief, not a backwoods lawman. His force badly needed reform. In the 1960s and early 1970s, the Columbus Police Department had been beset by corruption scandals, with officers fired for accepting bribes, and for taking part in large-scale 'burglary rings'. It also had a reputation for racism. Before McClung's arrival, black officers had been forbidden to arrest white suspects, while whites received higher pay. Some of the African-American police had fought in Vietnam, but on their return to the CPD they were unable to drink from the police station's whites-only water fountains. 'We had to go down to the basement and drink the water supposed to be for washing cars,' says former patrolman Robert Leonard.

In the summer of 1971, Leonard was one of seven black cops who decided to protest, by standing outside the mayor's office and cutting the US flag from their uniforms. All were dismissed, and a march in their support the following weekend was brutally crushed by their white former colleagues, triggering weeks of arson and riots. The seven sacked officers brought a lawsuit which took 22 years to resolve in their favour.

From the outset, the police believed that the stocking strangler was black. Both victims' cars had been found within a block of each other in Carver Heights, on the African-American side of Macon Road. At both crime scenes, the police had discovered pubic hair which did not come from the murdered women. As the coroner, Don Kilgore, later told reporters, in his opinion these displayed 'negroid characteristics'.

There was nothing very subtle about the CPD's investigative methods. Like their counterparts in Britain at the time, detectives usually tried to base a case on a confession. On 4 October, Mayor Mickle announced on TV that the police had a suspect. Ten days later, the CPD revealed at a triumphant press conference that a black odd-jobman, Jerome Livas, had been arrested for an unrelated crime, the murder of his girlfriend. In an all-night interrogation session, he had confessed to killing Jackson and Dimenstein as well, and disclosed details which 'only the killer could have known'. Columbus could relax. The extra patrols were stood down.

Florence Scheible, 89, was almost blind and walked with a Zimmer frame. On 21 October, a week after the press conference, she was raped and strangled in her home. Four days later, police found the body of the strangler's fourth victim, Martha Thurmond, 69, a retired schoolteacher. For a few days, McClung stuck to the claim that Livas had committed the first two: 'The evidence against him still exists,' he said. Then Carl Cannon, a Columbus Ledger reporter, got himself into the county jail and interviewed Jerome Livas. He again admitted not only the first two murders, but also those of Presidents Kennedy and McKinley, adding that he had been with Charles Manson when he butchered the actress Sharon Tate. 'Although Livas cannot read, he can sign his name,' Cannon wrote. 'And sign his name he did - to the Ledger "confession" and to a police "confession", which is the basis upon which he was labelled a suspect in the first two stocking stranglings.'

The city was seized by dread. 'There were literally hundreds of people on patrol every night, bumping into each other,' says Earnestine Flowers, a childhood friend of Carlton Gary who was working as a sheriff's deputy. 'There were guys from the hills of Tennessee who knew how to track people; Military Police from Fort Benning; the Ku Klux Klan; people from other police departments who wanted to volunteer. We had night lights, people up in trees; that new night vision thing which had just come out; dogs.'

In these conditions, it would not have been easy for a black intruder to insinuate himself into Wynnton. Former detective Richard Smith recalls answering an alarm call there: although he and his partner arrived within a minute, they had to park two blocks away, because so many other law enforcement vehicles had already responded. He worked 18-hour days for months. 'The old South has great respect and admiration for elderly people, and to see them treated that way was incredibly offensive. Most of us took it very personally.' Thousands of black males were stopped and searched in the streets, and subjected to humiliating 'field interviews'.

None of it was effective. On 28 December, between midnight and 4am, the strangler assaulted and killed Kathleen Woodruff, 74, widow of George C. Woodruff, president of the Columbus Chamber of Commerce and one of the city's most powerful men. The Woodruffs had been in Columbus since 1847, and it was they who in 1919 put together the syndicate which bought and saved the ailing Coca-Cola corporation for $25 million. Before he went into business, George Woodruff had coached the University of Georgia football team. Kathleen was strangled with the varsity scarf.

Seven weeks later, on 12 February 1978, came what Columbus cops still call 'the night of the terrors'. It began with an attempted burglary, supposedly by the strangler, at 5.15am at the chateaulike residence of a retired industrial magnate, Abraham Illges. An alarm was triggered and the police arrived, their tracker dogs fanning out through the woods. Two blocks away, Ruth Schwob, who ran a textile business founded by her late husband, awoke to find herself being straddled by a man in a mask, who was trying to strangle her with her tights. Expert in judo, she fought him off and managed to press a panic button. The police arrived within two minutes, at 5.45am.

Even as the squad cars swarmed round Mrs Schwob's house, the killer made his way to the home of Mildred Borom, 78 - diagonally opposite the Illges residence he had so recently left. He killed her with a cord from a Venetian blind.

Perhaps the night of the terrors scared even the strangler. For his last murder, he moved out to Steam Mill Road, a mile and a half from Wynnton. There he killed Janet Cofer, 61, a schoolteacher.

And then, for six years, nothing happened. The investigation continued, but the police had no real suspects. The years passed.

At the Georgia Diagnostic and Classification Prison near the little town of Jackson, death row lies deep within. After passing six electronic gates and two metal detectors, one is led to the junction of three gloomy tunnels stretching into the distance, echoing with the shouts of inmates. A final gate glides open. Carlton Gary stands on the other side. We enter a narrow meeting room with stools and plastic chairs, and the guard locks us in. Like all the prisoners, he wears a white T-shirt, white slacks, white rubber-soled shoes. Tall and muscular, he looks younger than his 54 years.

On death row, Gary has produced a body of striking artwork, some of which has been exhibited. In his late teens, he played bass professionally, and sometimes he breaks into song, in a pure, gospel tenor. He made little of these talents, and has had more than enough time to rue the consequences of crimes he has always acknowledged: robbery and dealing cocaine. 'That was my lifestyle. I'm not proud of it.' But the vehemence with which he denies the stranglings is palpable. 'I'm not Prince Valiant. But I'm not Satan, either.'

Gary spent his childhood in a three-room shack on 18th Street, Columbus, long since torn down. His father - later murdered by mobsters in Indiana - left when Gary was a baby, leaving him with his sister and his mother, Carolyn. It was not a stable upbringing. Earnestine Flowers lived just up the street: 'Carolyn was a lady of the evening. He would come home from school and she would be gone two or three days. She dated the soldiers from Fort Benning because they had food, money and liquor. He was emancipated at an early age.'

The shadow of segregation lay heavily across Columbus, and in the early Sixties, when Gary was 12, the family moved to Gainesville, Florida. There Gary's criminal career began: first stealing cars, then an arson attack when he burnt down a food store which had refused to accept his mother's cheque. In 1967, he left for the north east, where he made money through music, poolroom hustling and theft.

It was in 1970 that he was jailed for the crime which made him vulnerable to becoming a suspect for the stocking stranglings. That September, Gary's fingerprint was found in a hotel room where an elderly woman, Nellie Farmer, had been robbed, sodomised and strangled. My investigations have revealed no other evidence that Gary committed this crime, and he told the Albany police - who seem to have believed him - that his print was there because he had been asked to act as a lookout for the real killer, John Lee Mitchell, and to help him remove the victim's property. Mitchell was tried and acquitted of the murder. Sixteen years later, at Gary's trial for the Columbus stranglings, Mitchell testified that it had been Gary, not him, who killed Nellie Farmer.

After his parole in 1975, Gary was arrested again, in January 1977, for attempted burglary in Syracuse, New York. That August, he sawed through the bars of his cell and jumped more than 20 feet to the ground, breaking his ankle. After lying low for a few weeks, he got on the Greyhound back to Columbus. The police say he was there by the start of September 1977. Gary claims he didn't arrive until the end of the month - after Ferne Jackson's murder on 15 September. One thing on which there is no dispute is that for the first few weeks after reaching Columbus, he was wearing a plaster cast and could barely walk. How someone in that condition could have spirited himself undetected into and around Wynnton has never been explained.

The Columbus police have known about Carlton Gary since at least 16 February 1979, 10 months after the last of the killings, when his robbery spree came to an end. (Gary's first robbery came just three days after the last strangling. According to the prosecution at his trial, he had grown tired of murdering women from whom he stole nothing, and began to rob as an alternative outlet for his criminal energies.) Fleeing from a restaurant in Gaffney, South Carolina, he blundered into a swamp and was caught. He pleaded guilty and was sentenced to 20 years. The CPD correctly guessed he might also have been responsible for several robberies in Columbus. On 10 March 1979, detective Richard Smith offered him immunity from further prosecution in return for confessions. Gary readily agreed. At this barren stage of the murder inquiry, any black person from Columbus arrested for anything was considered as a possible suspect for the stranglings. Smith confirms he left Gaffney with Gary's fingerprints, and personally asked the Columbus print identification officers to compare them with the marks found at the murders. No match was found at the time. Seven years later, at the stranglings trial, the prosecution claimed that Gary's prints did match. Richard Smith cannot account for the discrepancy.

So how did Gary become a suspect? Responsibility rests with one man: former Columbus detective Michael Sellers.

In March 1984, five years after Smith's visit to South Carolina, Sellers was a young, ambitious cop, new to homicide, when Gary absconded from an open prison after another inmate threatened his life. The South Carolina authorities immediately told the CPD of Gary's escape and asked them to look out for him. It would not have been surprising had Sellers simply wondered who Gary was, discovered the Nellie Farmer case, and worked from there. But this isn't the story Sellers tells.

In October 1977, after the first two murders, a man called Henry Sanderson had his gun stolen in a burglary in Wynnton. Sellers' story is that seven years later Sanderson called him, saying he'd received a message that the police had found his gun. In fact, they hadn't, and neither had anyone phoned Sanderson. But Sellers says he thought that the gun might somehow be linked to the murders, simply because it had been stolen in the same neighbourhood. He decided to do whatever it took to find the weapon.

After contacting police forces across America, he tracked it down to Kalamazoo, Michigan, where the police had impounded it when someone tried to register it. This individual had been given it by an aunt in Indiana, who in turn had acquired it from her brother, who lived across the Chattahoochee River from Columbus in Phenix City, Alabama. The brother's name was Jim Gary. According to Sellers, Jim told him he'd bought it from his nephew, Carlton Gary, in 1977. The next step was to get a copy of Carlton's prints from South Carolina and compare them with the marks at the crime scenes. This time they matched.

But why did Sanderson call the police? What could explain the 'message' saying his gun had been found? Sellers says he learnt the answer some months later, when he phoned Sanderson to talk about the trial and his wife answered: 'My husband has Alzheimer's,' Sellers claims she said. 'He just got it in his mind. No one called him about the gun.'

Sellers, greying now, with a toothbrush moustache, leans across the table in a north Atlanta restaurant and lowers his voice. 'Sanderson called me the very day Carlton Gary got out of prison. Isn't that scary? I think it was God's doing. God was saying, "Here's one more chance to get him before it starts again."' By the time of the trial, he adds as an afterthought, Sanderson's Alzheimer's was more advanced, and he was 'too gone' to testify.

It makes a good story, but some of it is demonstrably untrue. Sanderson did testify at Gary's trial. Instead of being 'too gone' to testify, he displayed an impressive recall of events nine years earlier. When questioned about the loss of his gun he didn't say anything about messages from unknown cops.

So Gary became a suspect. A SWAT team eventually found him on 3 May 1984 in a motel in Albany, Georgia. The TV pictures shot as Sellers brought him back to Columbus show Gary grinning. 'The reason I was smiling,' Gary says, 'was they still hadn't told me why I was being arrested. I thought they were tripping on about those old robberies which were over and done with.'

Carlton Gary spent the next 27 months in solitary in the Columbus county jail. By the time his trial began in August 1986, he was withdrawn and depressed. It was not his only handicap.

The pre-trial stages of the case were heard by John Land, Columbus's chief judge. Land was one of Georgia's most powerful figures - the founder of a network known as the 'Fish House Gang', which made and broke political careers across the state. In 1956, Columbus's black civil rights leader, Dr Thomas H. Brewer, was assassinated in front of numerous witnesses by the owner of a department store. John Land was then District Attorney. It was on his watch that the killer was freed without being tried, on the grounds that he shot Brewer, a Ghandian physician aged 61, in self-defence.

In Georgia, when defendants cannot pay for their lawyers, the judges get to choose them. To Gary, Land assigned an experienced local lawyer, Bill Kirby. Gary wouldn't have trusted anyone assigned by Judge Land, and he didn't trust Kirby. (Ironically, Kirby remains persuaded of Gary's innocence, and insists that had he handled the trial and been properly funded, he might have won his freedom.) Instead, Gary wanted Bud Siemon from Atlanta, a Vietnam special forces veteran who specialised in death penalty trials and appeals.

On 28 August 1984, two full years before the trial began, Siemon stood before Land to say that he had been asked to become lead counsel. Land agreed, but he set down a condition: as Gary had declined the court's recommended attorney, Siemon would have to work on the case for nothing. Land didn't hear the trial itself. But his successor on the case, Judge Kenneth Followill, interpreted his ruling to mean that Gary should not receive a cent to meet the costs of witnesses, experts or an investigator. The implications were soon apparent. If the state presented scientific evidence, it would be heard unchallenged; if Gary said he had an alibi, there would be no money to find the witnesses who might support it. Siemon filed 140 separate motions with Followill asking for money to investigate the many avenues which needed funding. Followill refused them all. Siemon had brought in co-counsel Bruce Harvey from Atlanta, and Gary Parker, a Columbus African-American. Months before the trial started, the defence attorneys were facing personal bankruptcy. First Parker, then Harvey, were forced to withdraw. As Siemon comments, while the state was trawling for witnesses across the US, 'we couldn't even make long-distance phone calls.'

Years later, I met Land in his villa overlooking the Chattahoochee. Still upright at 86, he told me he had come to regret the segregationist beliefs he held as a younger man, and his role in the trial of Carlton Gary. Land now says Followill's decision to deny him funds for witnesses and experts was wrong, and when he made his ruling that Siemon would get no fee, that had not been his intention.

Terminate with extreme prejudice - part 2

By the time the trial got under way, the case presented by the District Attorney, former FBI agent Bill Smith, and his assistant Doug Pullen looked overwhelming. They had prints which matched Gary's from each of three homes where he was formally charged with murder; a woman who said she had survived his attack, and could identify him; and his own incriminating statement to the police. Admittedly, there were some weaknesses. Gary's pubic hairs had been compared to those found on the victims, and they did not match. Perhaps, Smith told the jury, this was due to the passage of time: Gary's hair had somehow changed. There was also some doubt over his blood type. The jury did not detain itself with these difficulties. On 5pm on 26 August 1986, they began to deliberate. Less than an hour later, they had their first verdict: guilty on all counts. Next day, they condemned him to death.

That night, the lawyer Gary Parker visited him in his cell. 'I told him he'd better buy himself some rubber underpants, and he laughed. His spirits were good. We couldn't believe the appeals system would ever leave such a travesty unchallenged.' Next day, he was taken to death row.

For years, says his long-time friend and correspondent, Wendy Murphy, a British dental hygienist, from Norfolk, he managed to stay sane by helping other inmates: his neighbour Jose High, for example, whom he taught to read. Self-taught in the law, he helped others file grievances against the petty injustices of a maximum security prison.

'I meditate a lot, I work out,' says Gary. 'What good does worrying about it do? It kills you with stress: I've seen guys in here die like that. As long as nothing physically has happened to me, I can walk right out of here. Sometimes I watch TV and it's raining, and I love riding in the rain. I see parks and animals - and then I stop myself. I tell myself, "No. You just don't let that stuff in."' In 1996, he married a woman from Phenix City, a nurse, and adopted her teenage daughter. Lately, however, the stress has begun to tell. After a four-year moratorium in executions caused by its change from electrocution to lethal injection, for the past two years Georgia has been culling death row at the rate of one prisoner every two or three months. Jose High is gone, along with other long-familiar faces. Gary has bad days, when a visitor may arrive to see him, but he feels too depressed to leave his cell.

Six years after the trial, in 1992, Gary's case reached its state habeas corpus review: his best chance to argue that he ought to get a new trial, on the grounds that his constitutional rights had been violated. One of his new lawyers, Jeff Ertel, performed a tireless investigation. He found witnesses who had been beyond Bud Siemon's reach, and used Georgia's Open Records Act to get access to a sealed dossier at the prosecution office in Columbus. As Ertel worked his way through it, it seemed that the pillars on which Gary's conviction rested were crumbling. First to go was the testimony of Gertrude Miller, who had been raped at her home in Wynnton 11 days before the first murder. The trial's highest drama came when she pointed at Carlton Gary in the dock, declaring in an even voice: 'It was him.' But the newly-discovered dossier indicated that when she was first attacked, Miller had said it had been so dark that she didn't know whether the intruder was black or white. Later, she went on to identify three other suspects in succession - all of whom looked different, and none of them like Gary. She claimed to have recognised him only a year after his arrest - after he had repeatedly been shown on television as the stranglings suspect, and after she was hypnotised by the police.

Ertel also found new material which cast doubt on Gary's statement to the police - the accuracy of which rested entirely on the memory and integrity of detective Michael Sellers. He had testified that Gary had been driven round Wynnton on the night of his arrest, and confessed, giving details which proved he must have been at the killings. Normally, CPD interrogations were taped or written down contemporaneously, but Sellers said he had gone home and written his notes from memory at his kitchen table at 4.30am. Gary had always claimed his interview was taped, and that he'd admitted nothing. Now Ertel found a copy of the alleged confession with tape time codes written between the lines. It suggested, Gary's lawyers told the court, that someone had transcribed a few innocuous passages to lend the document authenticity, then filled in the incriminating gaps. The prosecution disputes that it refers to Gary's interview.

Other documents cast doubt on the fingerprints. I showed them to Eddie Florence, an African- American Columbus cop turned preacher who had worked in fingerprints for 18 years. He pointed out the absence of any photographs of the latent marks in situ, before they were lifted. 'In a case like this, you'd always do that. It was set procedure. It would stop a lawyer in his tracks: take the breath out of him. We had a camera specifically designed.'

By early 1997, Gary's recourse to Georgia's state courts had been comprehensively blocked. He had one last shot: a federal habeas appeal - first to the US district court in Columbus, and then, with an ever slimmer chance of success, to the 11th Circuit of Appeals in Atlanta and the US Supreme Court. Once again, he had new lawyers: Jack Martin and Michael McIntyre in Atlanta. Meanwhile, as the appeal has proceeded - conducted not in a single hearing, but with paper briefs and occasional appearances over several years - new evidence has continued to emerge.

As Jeff Ertel was preparing the state appeal, he tried to discover what had happened to the semen gathered from the victims, in the hope of being able to use the DNA fingerprinting techniques invented since the trial. It seemed to be a dead end. At the hearings, prosecutor Pullen testified that the samples had been destroyed, on the bizarre grounds that they constituted a 'bio-hazard'.

Forensic science in the mid-1980s was simpler than it is today. In a case of rape, experts tried to narrow the range of suspects by looking at blood groups. First they would try to establish the basic 'A, B, O' category. The next step was to find out whether the rapist was a 'secretor' - whether normal normal amounts of the A, B, O blood group markers, or 'antigens', were secreted into other bodily fluids, such as semen. About four-fifths of the population are secretors.

At Gary's trial, the prosecution expert, John Wegel, testified that he tested seminal fluids from three of the bodies, concluding that the killer was a non-secretor, or someone who secreted at much lower levels than normal. However, Gary had given a saliva sample after his arrest. It showed he was a regular, blood group O-secretor. Maybe Gary secreted the antigen in his saliva, but not his semen, Wegel suggested, or maybe he had been a non-secretor at the time of the murders but had become a secretor now.

This seemed to me the case's weakest point, so I found an expert, Dr David Roberts, who lived near me in Oxford, and showed him the transcript. He thought Wegel's claims were dubious, but to be certain, he needed his laboratory notes - which the prosecution had repeatedly claimed did not exist. Gary's lawyer, Jack Martin, finally discovered them in April 2000, in a box labelled: 'Throw this file away'. When Dr Roberts saw them, he swore an affidavit, saying that Wegel's methods were hopelessly flawed: he had used the wrong forensic test. The claims that Gary might have secreted in his saliva but not his semen, or that he may have changed over time, had no basis in science.

This persuaded Judge Hugh Lawson - who heard the early part of the federal appeal, before the appointment of Clay Land - to hold a hearing. There, Wegel stuck to his guns. Gary might not secrete in his semen, he insisted, and so he might be the killer. There was only one way to ascertain the truth: a controlled test of Gary's semen. This Lawson refused to permit. So I organised it myself.

Gary ejaculated on to a piece of paper, wrapped it in clingfilm and put it in an envelope, which I hid in a document file and smuggled out of the prison. Then, in front of me, he plucked some hairs from his head. Following instructions from my British expert, I let the semen dry in my hotel room and then sent it and the hair to a specialist lab in California. There, Dr Brian Wraxall - once Wegel's college tutor - DNA matched the hair roots and semen to establish the semen came from Gary. Then he did the secretor test. There was now no room for doubt. Gary was a strong blood group O secretor. He compared his results with those that Wegel obtained when he tested the best sample from the strangler - from a neat semen trace left on Martha Thurmond's body in 1977. The antigen level in Gary's semen was at least 3,000 times higher. Martin had already obtained an opinion from a scientist who happened to be head of the Alabama state crime lab. In his view, if a semen test showed Gary to be a strong secretor, 'he cannot be the killer.'

So far, the court has refused to accept this evidence. The prosecution appeal lawyer, Georgia's assistant Attorney-General Susan Boleyn, argues that the tests are irrelevant. At most, she says, they would prove that Gary did not rape the victims - but other evidence, such as his confession, still proved he was guilty of murder. In her view, 'There is nothing significant before this court.'

Back in 1992, Ertel had made another important discovery in the unsealed files. The strangler had bitten the left breast of his last victim, Janet Cofer, leaving a deep impression. Documents told how a local dentist, Sonny Galbreath, had made a cast of the strangler's teeth. It seemed to be a reasonable inference that if the cast matched Gary's teeth, it would have been used at the trial. The file said Galbreath still had the teeth cast. So Ertel called him from Atlanta and arranged to see him in Columbus. When he got there, he was disappointed: 'Dr Galbreath told me he had destroyed the cast. There was nothing we could do.'

There the matter rested until April 2001, when I met Sonny Galbreath. A thin, rangy man who once blew the tops off several fingers with a hunting rifle, he revealed: 'I do know the models are still in existence.' He had kept them until the year after Ertel's visit, when he gave them to the coroner, Don Kilgore. He went on to make a remarkable admission. Before Ertel came to visit, he said, he called his best friend and 30-year shooting partner - then DA Doug Pullen. 'Doug said, "On no account can he look at those models. You don't show him anything."' What reason did Pullen give? Galbreath said: 'You know, for some reason or another, he was considered shaky by the bar association, and they were trying to catch him doing something.' In fact, Ertel's reputation with the bar was excellent.

Pullen has refused to discuss the case with me. Whatever the truth, in another interview last year, backed by an affidavit, Galbreath added another observation. One of the killer's top front teeth displayed an unusual and striking deformity - a 'mesial rotation': in effect, it was twisted out of alignment by between 20 and 40 degrees. The killer's deformity would have been noticeable every time he smiled. I interviewed five people who knew Gary at the time of the stranglings, including the friend who grew up with him, the former law enforcement officer Earnestine Flowers. They were unanimous: his teeth are and have always been perfectly straight.

So what happened to the tooth cast? Several witnesses say that after the dentist gave it to Kilgore, he kept it in his desk, and liked to show it to visitors. Kilgore is dead. Last May, I called his widow, Karen. She promised to look for it, and asked me to visit the following Sunday. When I called to confirm, she said: 'I'm sorry, honey, I can't see you after all.' She had consulted her daughter's godfather, Ricky Boren, who told her not to see me because 'the case is under appeal'. Boren, now deputy chief of the CPD, was Sellers' main colleague during the investigation and was present at Gary's arrest, interrogation and trial. At a hearing last December, several members of the Kilgore family said they remembered the strangler's tooth cast. None of them knew where it could be.

Defence lawyers know that American courts, especially those in the south, can be rigid about their strict procedural rules: time and again, new evidence will be excluded because judges will say it has been filed too late. In several notorious cases, prisoners have been executed, with evidence that appears to exonerate them left unheard.

It now looks as if this is the fate that awaits Carlton Gary. In a ruling in April, Judge Clay Land declined to consider the tooth cast at all. Although Dr Galbreath appears to have misled Jeff Ertel when he said the cast had been destroyed, it was the defence which was negligent at Gary's state appeal, the judge says: instead of believing him, they could have issued a subpoena, or asked for a court order insisting the cast be found. Gary 'has failed to demonstrate that the facts upon which his claim rests could not have been discovered with reasonable diligence during the state habeas proceedings.' This lack of 'due diligence' means the cast issue is closed.

In what is likely to be the final round of argument in Gary's federal appeal, Gary's lawyer, Jack Martin, has asked Land to reconsider this decision. If he won't, says Martin, former prosecutor Pullen 'will avoid any inquiry into what happened with the bite mark cast. This is very troubling.' In his plea to the jury to pass a sentence of death, Bill Smith quoted Lincoln's Gettysburg address: 'The world will little note nor long remember what we say here, but it can never forget what they did here.' Smith said the world would soon forget his words, but the jury's sentence would be remembered always: 'You will set the benchmark, you will set the benchmark for justice in our state.'

A benchmark for justice: the systematic hiding of evidence which left the jury to make up their minds on the basis of evasions and half-truths. 'If murder is the dishonest taking of a human life, then what are these people doing?' asks Bud Siemon. 'What is the difference between murder and taking a life by lying and concealing evidence?'

Gary Parker, Siemon's one-time co-counsel, puts the case in the context of Georgia and its history - where black defendants convicted of killing white victims are still far more likely to face execution. 'The crime happens, the mob gathers. Far too often, the question is, which nigger's neck are we going to put the noose around?'

The Big Eddy Club, David Rose's book on the Columbus stranglings, will be published next year by HarperCollins