(CBS/AP) PHOENIX - An Arizona woman sentenced to death in the notorious 1989 killing of her 4-year-old son had her conviction thrown out Thursday as a federal appeals court ruled that her case was tainted by a detective who had a history of lying under oath.
The ruling marked a surprising turn in a case that made national headlines with the brazen and gruesome nature of the crime. Prosecutors said Debra Milke, now 48, dressed up her son Christopher in his favorite outfit and told him he was going to see Santa Claus at a mall during the holidays.
Instead, he was taken into the desert by her boyfriend and another man and shot three times in the back of the head as part of an alleged plot by Milke and the two other defendants to collect a $50,000 life insurance policy.
Milke would have been the first woman executed in Arizona since the 1930s had her appeals run out. The Arizona Supreme Court went as far as to issue a death warrant for Milke in 1997, but the execution was delayed because she had yet to exhaust federal appeals.
A three-judge panel of the 9th U.S. Circuit Court of Appeals ruled Thursday that the prosecution failed to disclose information about a history of misconduct by former Detective Armando Saldate Jr., who testified that Milke confessed to plotting her son's murder.
The evidence against Saldate included multiple court rulings in other cases in which the detective either lied under oath or violated suspects' Miranda rights during interrogations.
Prosecutors are required to provide a defendant's lawyers with material that might support a not guilty verdict, including material that could undermine the credibility of a prosecution witness. But there was no other witness or recording of Milke's alleged confession, who proclaimed her innocence.
"No civilized system of justice should have to depend on such flimsy evidence, quite possibly tainted by dishonesty or overzealousness, to decide whether to take someone's life or liberty," Chief Justice Alex Kozinski wrote in the decision.
The trial amounted to "a swearing contest" in which the judge and jury ultimately believed the detective over Milke, but they didn't know of his record of dishonesty and misconduct, Kozinski wrote.
The ruling reversed a U.S. District Court judge's ruling and ordered the lower court to require Arizona authorities to turn over all relevant personnel records for the detective. Once the material is produced and defense lawyers have time to review it, prosecutors will have 30 days to decide whether to retry her. If they don't, she will be released from prison.
The Arizona Attorney General's Office said it was reviewing the case and will likely file an appeal. Maricopa County prosecutors had yet to read the ruling and had no immediate comment on the decision, spokesman Jerry Cobb said.
Rick Romley, who was the county attorney from 1989-2004, said he remembers that the facts were quite strong against Milke and there never was a question in his mind that she wasn't guilty.
"If she walks, it's a travesty of justice," Romley told CBS affiliate KPHO-TV. "You just can't get around that."
In 2009, defense lawyer Michael Kimerer said his client maintains her innocence and was a loving mother who still grieves her son's death.
"Our main concern is the fact that I have a client that never confessed and a police detective who said she gave a confession," Kimerer said then. "There was no tape recorder, no witnesses, nothing. Just his word."
Milke is one of three women on death row in Arizona. All three are imprisoned at the state prison for women in Goodyear.
The two men convicted in the Milke's case, Roger Scott and Milke's former roommate James Styers, are both on death row at a prison in Florence.
Scott confessed during a police interrogation and led detectives to the boy's body. Neither Scott or Styers would testify against Milke.