Death penalty opponents praised Gov. Mark R. Warner's order for DNA testing that could determine whether Virginia sent an innocent man to the electric chair in 1992.

Warner said Thursday he ordered the tests because of technological advances that could provide a level of forensic certainty not available when initial DNA tests were conducted.

If the tests show Roger Keith Coleman did not rape and kill his sister-in-law in 1981, it will mark the first time in the United States that an executed person has been scientifically proved innocent, according to death penalty opponents.

"This is a proper action for the governor to take," said Richard Dieter, executive director of the Washington, D.C.-based Death Penalty Information Center. "It's not right to shy away from a difficult question or even shy away from reopening cases when there is a chance that something new might be learned."

Coleman was convicted and sentenced to death in 1982 for the murder of 19-year-old Wanda McCoy, his wife's sister, who was found raped, stabbed and nearly beheaded in her home in the coal mining town of Grundy.

His attorneys argued that he did not have time to commit the crime, that tests showed semen from two men was found inside McCoy and that another man bragged about murdering her. Coleman was executed May 20, 1992.

Four newspapers and Centurion Ministries, a New Jersey organization that investigated Coleman's case and became convinced of his innocence, sought a court order to have the evidence retested. The Virginia Supreme Court declined to order the testing in 2002, so Centurion Ministries asked Warner to intervene.

For months, his legal advisers have been negotiating with Centurion Ministries and with Edward Blake, the forensic scientist who did the initial DNA tests. Blake has kept the DNA sample frozen since 1990 in a lab in Richmond, Calif., and had balked at returning the evidence to Virginia, claiming his lab should do any new testing.

Warner, a Democrat who leaves office Jan. 14, said Thursday the negotiations were completed. The first of two samples was sent last month to Ontario's Centre of Forensic Sciences in Toronto, and a second batch will be sent there soon, he said in a news release.

"This is an extraordinarily unique circumstance, where technology has advanced significantly and can be applied in the case of someone who consistently maintained his innocence until execution," said Warner, who is considering a presidential bid in 2008.

"I believe we must always follow the available facts to a more complete picture of guilt or innocence," he said.

A former prosecutor in the case did not object to the tests and said he was confident they would confirm Coleman's guilt.

Tom Scott said a mountain of other evidence pointed to Coleman as the killer: There was no sign of forced entry at McCoy's house, leading investigators to believe she knew her attacker; Coleman was previously convicted of the attempted rape of a teacher and was charged with exposing himself to a librarian two months before the murder; a pubic hair found on McCoy's body was consistent with Coleman's hair; and the original DNA tests placed him within a fraction of the population who could have left semen at the scene.

DNA tests in 1990 placed Coleman within the 2 percent of the population who could have produced the semen at the crime scene. Additional blood typing put Coleman within a group consisting of 0.2 percent of the population. His lawyers said the expert they hired to conduct the test misinterpreted the results.