The cases were connected in only two respects. Each was a shocking miscarriage that exposed deep flaws in the way the criminal justice system works in the US. And each of the three men could thank for their release an independent, non-profit body called the Innocence Project, working on the assumption that the law must acknowledge when it has made a mistake.
No one knows how many wrongful convictions occur in the US every year, but studies suggest anywhere from 2 to 5 per cent of the country's overall prison population of more than 2 million - anywhere between 40,000 and 100,000 people - may be innocent. Since the Project was founded in 1992, more than 250 people have been exonerated through DNA testing, including 17 under sentence of death. The Project is working on 300 cases, but these are plainly the tip of an iceberg of error.
On Wednesday, three cases were brought to a happy end. But the shortcomings of the system will continue - starting with witness mis-identification, responsible for three-quarters of the miscarriages of justice taken up by the Project and later corrected by DNA evidence.
But not only can dubious evidence be manufactured; solid evidence can be suppressed. Take the Michael Morton case, in which prosecutors withheld a statement by the couple's son saying the father was not the killer.
Then there is the surprisingly widespread problem of false confessions, whether extracted by police intimidation or as part of a plea bargain struck by a defendant with prosecutors in return for a shorter sentence.
Other factors that can put an innocent man behind bars include incompetent and ill-paid publicly appointed defence lawyers, and the use of informants and jail stool pigeons, many of them (as in the case of Obie Anthony) only too ready to provide suitably damning evidence in return for a reduction in their own term.
Then there is junk science, of the kind that may have led to the actual execution by Texas in 2004 of an innocent man. The case of Cameron Todd Willingham, convicted of killing his three young children by arson, may yet come back to haunt the presidential campaign of the state's Governor Rick Perry, who allowed the capital sentence to be carried out despite overwhelming evidence that the crucial forensic "proof" of arson provided by expert witnesses at Willingham's trial was worthless.
And a mistake, once made, can be desperately hard to undo. No one likes to admit they have made a mistake, and least of all a criminal justice system, that is supposed to be the embodiment of the majesty of the law. Nor is it always easy to persuade public opinion, obsessed with "law and order", that a miscarriage of justice has taken place.
At which point enter the Innocence Project. Founded in 1992 as part of the Cardozo School of Law in New York City, it is an independent non-profit body, originally set up by two lawyers, Peter Neufeld and Barry Scheck.
The organisation has flourished, and is now the spearhead of a worldwide Innocence Network, embracing 55 affiliated organisations in the US and beyond.
The Project takes on cases only where new scientific evidence might prove a convicted person is factually innocent. Its true stroke of genius, however, has been to harness the energies of college law schools to that end.
The genesis of the Project was the advance in DNA technology, with its ability to establish guilt or innocence incontrovertibly. But increasingly, the Project is focusing on other less clear-cut imperfections of the system, including misidentification and false confessions.
Today, those imperfections are entering public consciousness. The trend is most visible over the death penalty, where mistakes are irrevocable, and where most Americans now favour sentences of life without parole.
"I thank God this wasn't a capital case. I only had life," Morton said. Troy Davis, put to death last month by the state of Georgia despite huge doubts about his guilt, was not so fortunate.
Barry Gibbs
With the help of the Innocence Project, it emerged Gibbs had been framed for murder in 1988 by Louis Eppolito, the New York police detective assigned to investigate his case. Eppolito was later convicted of carrying out eight murders for the Mafia. After 17 years in jail, Gibbs was released in 2005. He won a US$9.9 million settlement - New York's largest civil rights payout.
Dennis Fritz and Ron Williamson
In 1988, Ron Williamson was sentenced to death and Dennis Fritz to life in prison for the rape and murder of a 21-year-old waitress in Oklahoma six years earlier. A witness statement from a man named Glenn Core claimed Williamson was at the bar where the victim worked on the night of her murder. After Fritz appealed to the Innocence Project for help, DNA tests revealed sperm samples from the crime scene did not match Fritz or Williamson, but did match Core. After serving 11 years each - during which Williamson came within five days of being executed - they were exonerated and released in 1999.
Kenny Waters
Waters was found guilty of murdering his neighbour, Katherina Reitz Brow, in Massachusetts in 1983. The conviction was based on a statement from his former girlfriend Brenda Marsh's new partner, who offered the information two years after the crime in the hope of financial gain. Marsh initially denied the claims but changed her story when police warned that if she did not corroborate her partner's account, she would be charged as an accessory to murder and her children taken away. Waters' sister, Betty Anne, put herself through law school and worked with the Innocence Project to ensure the conviction was overturned. After 18 years in prison, he was exonerated using DNA evidence in 2001. He died six months later aged 47. The murderer has not been found.
- Independent
