HOUSTON, Dec. 1 - Hours before she was to have been executed for the murders of her husband and children, a Texas woman was spared on Wednesday when Gov. Rick Perry granted her a 120-day reprieve to review disputed evidence that convicted her.

Although Mr. Perry said that after a lengthy review of the case "I see no evidence of innocence," he accepted a recommendation made Tuesday by the Board of Pardons and Paroles to delay the execution of the woman, Frances Newton.

The delay is to be used to apply "new technology" in a retesting of a gun prosecutors say Ms. Newton used and a skirt she was wearing at the time of the killings in 1987.

Ms. Newton, 39, who has maintained her innocence throughout her 16 years on death row, took the news with a smile at the execution unit, in Huntsville, a prison spokeswoman said, and said she was not surprised because "I was hopeful someone would hear us." One of her lawyers, John LaGrappe, said that he had spoken to her earlier and that she was praying with her mother and members of a Baptist prison ministry and was resigned to her death, saying "I will finally be reunited with my family."

The state charged that on April 7, 1987, Ms. Newton shot and killed her husband, Adrian, and their two small children, Alton and Farrah, for $100,000 in life insurance. Ms. Newton said that she had come home to find them murdered and that a gun she had earlier found in the house and removed had nothing to do with the killings. Her lawyers at the time failed to investigate her claims, her appeals lawyers later claimed.

Ms. Newton's lead lawyer, David R. Dow, who said he was on the phone with the United States Supreme Court seeking a stay when the governor's action was announced about 4 p.m., was jubilant.

"I am extremely relieved and pleased that Governor Perry recognizes that the question about her innocence is an actual question," he said. Mr. Dow, a University of Houston law professor whose Innocence Network represents inmates claiming wrongful conviction, said his next step was to arrange for retesting of the gun and the skirt.

District Attorney Charles A. Rosenthal Jr. of Harris County, whose office prosecuted Ms. Newton and who had opposed a reprieve, said, "I'm very disappointed." Mr. Rosenthal noted that earlier this week both the Texas Court of Criminal Appeals and the United States Court of Appeals for the Fifth Circuit turned down a stay of execution.

In an effort to sway the governor, Mr. Rosenthal said, he submitted an affidavit on Wednesday from the Texas Department of Public Safety saying that the test on the skirt, which it had originally performed for the trial in 1988, could not be duplicated today.

"Rick didn't call me," he said of the governor, a fellow Republican. "I kind of thought he would."

The skirt had tested positive for nitrites, which prosecutors said showed that Ms. Newton had fired a gun. But the defense claimed the chemical was only residue of garden fertilizer.

The .25-caliber automatic pistol that Ms. Newton said she had removed from the house was tested at the Houston police crime laboratory and presented in court as the weapon used in the killings. But the lab was later tarnished by revelations of sloppy procedures. Ms. Newton's lawyers have claimed that the gun should show traces of the victims' blood if fired in the point-blank manner described by the state and that no such evidence was produced.

Mr. Rosenthal said he was confident that any review would back up the state's case, which he said had already survived the scrutiny "of 50 or 60 people."

"On the other hand," he said, "it doesn't make any difference to me if she is executed today or in 120 days." He said that the state court that tried Ms. Newton in 1988 could set a new execution date around April, after the reprieve runs out.

Mr. Dow said the next step was to talk to the district attorney's office about gaining access to the gun and the skirt. He said it would be difficult after so long to investigate other leads.

The reprieve capped days of jockeying over the case and put off what would have been Texas's 24th execution of 2004.

The tension built Tuesday after the pardons board, in an action the governor's office could cite no precedent for, recommended 5 to 1, without comment, that Governor Perry grant Ms. Newton a 120-day delay.

Among those appealing to Mr. Perry to grant it was Mayor Bill White of Houston, a Democrat, who faxed him a letter on Wednesday saying, "as a supporter of capital punishment, I believe it absolutely necessary that there are legal safeguards that would remove any questions or doubts that an innocent person may be executed."

Mr. Perry acted about 4 p.m., his office releasing a statement quoting him as saying: "Justice delayed in this case is not justice denied. The courts are the ultimate arbiters of evidence, and this case is now back in the hands of the courts."

Soon, Ms. Newton was on her way back to the women's death row in Gatesville, near Waco, where she is the longest resident of the nine women there.