Now that the death penalty will no longer be debated in the name of Roger Keith Coleman, some observers say it's unlikely DNA testing will ever be used in Virginia to absolve an executed man.

That's because the unique circumstances of Coleman's case are becoming even more rare as time passes: Coleman was convicted before the advent of DNA analysis, which was later used to discount his claim of innocence by testing evidence that is not preserved in every case.

"This is a part of scientific and legal history that may now be over," said David Bruck, a law professor who directs the Virginia Capital Case Clearinghouse at Washington and Lee University.

Before the announcement Thursday that DNA tests confirmed Coleman raped and murdered his sister-in-law in 1981, his supporters had hoped his case would become the first in which science would clear someone executed in the United States.

Had that happened, advocates were poised to make Coleman the poster boy in their movement to abolish the death penalty.

Finding another such case, at least in Virginia, may prove difficult.

In capital murder cases as old as Coleman's, the evidence likely has been lost or destroyed, Bruck said. In more recent cases, the evidence is likely to have already been tested by the time the defendant is convicted.

"It's not going to be very often" that a case like Coleman's comes up, said Richard Dieter, executive director of the Death Penalty Information Center in Washington, D.C.

Of the 1,004 executions carried out nationwide since 1977, Dieter said he is not aware of a disputed case in which there currently is biological evidence available for testing.

But considering the number of living defendants who have been exonerated by DNA testing, Dieter said it's logical to assume the same thing could happen with an executed one.

According to the Innocence Project, a network of attorneys that works for the wrongfully convicted, DNA testing has been used to clear 172 people wrongly convicted of crimes in 31 states since 1989. That includes Edward Honaker, a Roanoke man convicted of rape.

Of the 1,004 people executed since 1977, "I think there's a high probability that at least a few of them -- one or two, maybe more -- were innocent," said Dieter, whose organization opposes capital punishment.

On the other side of the issue, the results of Coleman's DNA tests were being used to debunk such statements.

"The next time a death penalty opponent insists that some killer on death row is innocent, remember that's what they told us about Roger Keith Coleman," said Michael Paranzino of Throw Away the Key, a Maryland organization that works to reduce violent crime.

"Thug huggers have every right to claim innocence for every cold-blooded murderer out there, and we have every right to ignore them," he said.

"Death penalty opponents have long overreached, but this time they got caught. This is a watershed moment that will further weaken their efforts to protect killers from facing justice."

Although state courts have ordered posthumous DNA tests in a few cases -- with inconclusive results in Georgia and a finding in Florida that a death row inmate who died of a heart attack was innocent -- Warner is the first governor to order such tests.

He was able to take the unprecedented step because a semen sample recovered from Coleman's victim had been preserved over the years in the freezer of a California scientist.

Edward Blake tested the evidence in 1990 at the request of Coleman's lawyers. Using the best technology that existed at the time, Blake could only narrow the potential pool of suspects to include Coleman, who was convicted in 1982 on circumstantial evidence by a Buchanan County jury.

Coleman was executed in 1992, proclaiming his innocence for the last time as he sat strapped in the electric chair.

When Warner decided late last year to put lingering questions to rest by ordering more advanced DNA testing, the process showed Coleman to be a liar as well as a rapist and murderer.

In the years before those final tests were conducted, Blake had refused to return Coleman's DNA extract to Virginia, saying he was afraid the state would destroy the evidence in keeping with its normal practice for closed cases.

"It would be a whole different case with Joseph O'Dell if Blake had tested the evidence," said Jack Payden-Travers of Virginians for Alternatives to the Death Penalty.

O'Dell was executed in 1997 amid questions about his innocence, and state officials then destroyed evidence that had not been subjected to more sophisticated DNA testing.

The state also strongly opposed efforts to test the evidence in Coleman's case.

Although disappointed by the results in the Coleman case, Payden-Travers and other death penalty opponents said a single case should not be used to validate every execution.

"Given the extraordinary number of post-conviction exonerations and the thousands more cleared by DNA while awaiting trial, questions and doubts about the fairness of our justice system are pervasive," said Peter Neufeld, co-director of the Innocence Project.

"Nobody can be satisfied with the correctness of 1,000 based on the correctness of one."