Henry Watkins "Hank" Skinner was supposed to be executed tomorrow, but last Tuesday a Gray County, Texas, District Court judge pushed the date back one month, to March 24. Skinner has been on Death Row in Texas since 1993, awaiting execution for the murder of his girlfriend and her two sons. He has maintained his innocence since his arrest, and investigators from the Northwestern University Journalism School's Medill Innocence Project have shot numerous holes in the prosecution's case. But Texas officials refuse to conduct a simple DNA test that could point to the condemned man's innocence or cement his guilt.

Skinner's scheduled lethal injection comes shortly after Texas Gov. Rick Perry has removed sympathetic panelists from the state forensic committee's investigation into the case of Cameron Todd Willingham and replaced them with panelists critics say are stymieing the investigation. Willingham was executed in 2003 for murdering his three daughters by setting fire to his house. Nine arson experts and an investigation published in the New Yorker last year have since made a strong case that Willingham was innocent of the crime.

At the same time, Texas, a notoriously enthusiastic enforcer of the death penalty, continues to lead the nation in DNA exonerations (one county in Texas has produced more genetic exonerations than all but three states). Which makes it all the more disturbing that biological evidence from Skinner's crime scene remains untested, at the behest of prosecutors and backed up by the courts. You'd think given recent headlines that Texas might be a bit more reluctant to execute a possibly innocent man.

Skinner doesn't dispute that he was in the house at the time his girlfriend was bludgeoned to death and her sons were stabbed to death. But he says he was unconscious at the time, knocked out by a near-lethal mix of alcohol and codeine. He was convicted because of his presence at the crime scene, because he had small spots of blood from two of the three victims on his shirt, and because of the testimony of a neighbor, Andrea Reed, who happens to be an ex-girlfriend of Skinner's. Reed says Skinner came to her shortly after the crime and implicated himself to her. According to court records, Skinner then told Reed a number of other implausible stories about who committed the murders.

Skinner's case has been championed by the Medill Innocence Project, the team of professors and students that exposed deep flaws in the Illinois death penalty system (ultimately leading to a moratorium on executions in the state), and has freed 11 people from prison, including five who had been condemned to death. After years of investigation, the project has revealed a number of shortcomings in the state's case against skinner. Among them:

· Andrea Reed has since recanted her testimony. She now says she was pressured by police and prosecutors to falsely incriminate Skinner. In an interview with Medill students, she added that, "I did not then and do not now feel like he was physically capable of hurting anybody." · The untested DNA included blood taken from the murder weapons, skin taken from under the fingernails of Skinner's girlfriend, a rape test taken from her that included semen, and other blood and hair found at the scene. Skinner asked his attorney to request the evidence be tested in a letter written in 1994. The attorney never made the request, stating later that he feared doing so would implicate his client. · Skinner's girlfriend had been stalked by an allegedly lecherous uncle, Robert Donnell. Witnesses say Donnell had approached her at a party she attended the night of her death. She left frightened, and he appeared to have followed her. A friend says the uncle had raped her in the past. Days after the murders, a neighbor reportedly saw the uncle thoroughly cleaning and repainting his truck. · Skinner's court-appointed attorney was a former prosecutor who had actually prosecuted Skinner on a minor assault and car theft charge years earlier. Skinner's two prior crimes—which his own attorney had prosecuted—were used as aggravating factors in the death penalty portion of his trial. · According to a new report (PDF) by toxicology specialist Harold Kalant, a moderate drinker with the levels of codeine and alcohol Skinner had in his blood would have been comatose or dead. A heavy drinker may have been rousable, but would have been "stuporous," unlikely to have the coordination necessary to carry out three murders involving multiple stabbings and bludgeonings.

It isn't difficult to see why prosecutors don't want the DNA tested. They have an unsympathetic suspect that they can place at the scene of the crime. If DNA suggests someone else bled or fought in the house that night, it doesn't conclusively prove Skinner is innocent, but it does (or at least ought to) raise enough reasonable doubt to prevent his execution. In 2000 DNA tests were conducted on blood taken from a roll of gauze and a cassette tape found in the house; that blood didn't match Skinner, his girlfriend, or her sons.

The first possible outcome of testing the remaining evidence is that the DNA will match Donnell, the allegedly lecherous, threatening uncle. Donnell has since died. If tests show Donnell's flesh under the victim's fingernails, or his blood or semen at the scene, the state is left with the strong possibility that they let a murderer go free, brought an innocent man within a week of execution, and no longer have a live body they can try, convict, and execute.

The second possibility—that the untested evidence came from other, unknown parties—wouldn't necessarily prove Skinner's innocence, but it would certainly complicate the state's case against him. But that's still no reason to refuse the tests. If we're going to execute people for particularly heinous crimes, we have a moral obligation to ensure that every reasonable possibility of the suspect's innocence has been explored and exhausted. Ignoring evidence that complicates things falls well short of that obligation.

The third possible outcome from testing the remaining biological evidence is that DNA will come back a match only to Skinner or the victims. That would go a long way toward affirming Skinner's guilt. All the more reason for conducting them.

After a conviction, the criminal justice system tends put a premium on finality, setting a high bar for reopening or retrying old cases. Given the Willingham case and the spate of exonerations across Texas, perhaps it's time the state put less emphasis on finality, and more on certainty. DNA testing in Skinner's case may not bring us closer to closing those 1993 murders, but it will bring us closer to discovering the truth about them. In a capital case especially, that alone should be reason enough to to go through with the tests.

Radley Balko is a senior editor at Reason magazine.