After deliberating less than eight hours, a jury on Thursday found former LAPD detective Stephanie Lazarus guilty of first degree murder for killing her ex-boyfriend's wife in 1986.

Lazarus faces 27 years to life in prison with the possibility of parole for the murder plus a gun enhancement imposed by the L.A. Superior Court jury, with sentencing scheduled for May 4.

Prosecutors alleged Lazarus was obsessed with her romantic rival, Sherri Rasmussen, and ruthlessly attacked and shot the 29-year-old nurse, then staged the scene to look like a botched robbery. Rasmussen had been married for three months to Lazarus' ex-college sweetheart, John Ruetten, who found her body at their Van Nuys condominium on Feb. 24, 1986.

In this July 29, 2009 file photo, former Los Angeles detective Stephanie Lazarus appears in court in Los Angeles. Lazarus on Thursday, March 8, 2012 was found guilty of the 26-year-old murder of the wife of her former lover in a case that hinged on a single piece of evidence DNA from a bite mark on the victim's arm. (AP Photo/Nick Ut, File)

Police initially believed that robbers had committed the crime. After they re-opened the case, DNA testing from a bite mark swabbed from the victim led them in 2009 to Lazarus, who was working as a detective in LAPD's downtown-based art-theft unit.

Rasmussen's family held hands in the courtroom and several broke down in tears as the guilty verdict was announced. They did not speak to reporters afterward.

"This 26-year nightmare has concluded with a positive identification of the person who killed (Nels and Loretta Rasmussen's) daughter and the intent with which she did it," said attorney John Taylor, who represents the victim's family.

Lazarus sat expressionless in the courtroom and did not react as the verdict was read. Her family quickly exited the courtroom without speaking.

Her defense attorney, Mark Overland, said he felt the quick decision by the jury indicated they did not fully examine all the evidence.

"We never had a chance," Overland said.

He promised to appeal, saying he had not been allowed to present an alternative theory of the crime - that robbers had committed the murder. He described his client as "definitely disappointed."

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