LOS ANGELES (CBS) — A jury of eight women and four men began deliberating Tuesday the murder case of an LAPD detective who is accused of killing her ex-boyfriend’s wife.

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Closing arguments ended Tuesday afternoon in the case against Stephanie Lazarus, 51, who is charged in the 1986 murder of 29-year-old nursing supervisor Sherri Rasmussen. Rasmussen was shot to death in Van Nuys.

The murder case was cold until DNA evidence linked Lazarus to a bite mark on Rasmussen’s arm. The former art theft investigator then retired from the LAPD after her arrest in 2009.

Deputy District Attorney Shannon Presby said the only two explanations for Lazarus’ DNA being found in the bite mark on Rasmussen’s arm would be that she either “bit Sherri when she was attacking her” or that someone had to plant the evidence in the coroner’s office to try to frame the veteran police detective.

This case is a banquet of evidence,” Deputy District Attorney Shannon Presby told the Los Angeles Superior Court jury in his rebuttal argument. “This (DNA) is not the only piece of evidence.”

In his closing argument, defense attorney Mark Overland countered that the evidence raised “questions of reasonable doubt” and “point to the innocence of Stephanie Lazarus.” He disputed the DNA collected from a blanket and towel found at the crime scene 26 years ago. Overland also argued that the coroner made multiple errors during the investigation.

Deputy District Attorney Paul Nunez argued Monday that the motive for Rasmussen’s murder was jealousy and that DNA and circumstantial evidence should be the basis of her conviction.

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A jury was also shown a letter Lazarus sent to the mother of her ex-boyfriend, John Ruetten, after the two broke up.

“I don’t think I’ll ever understand John’s decision,” it reads. “I’ll never accept his decision to marry Sherri. It should be me, right?”

Lazarus had been in a sexual relationship with Ruetten, whom she met in college, but he testified during the trial that he never considered her his girlfriend and continued to date other women while he was seeing her.

Ruetten and Rasmussen were married Nov. 23, 1985. Three months later, the Glendale Adventist Medical Center nursing supervisor was shot three times in the chest at the couple’s Balboa Boulevard townhouse.

Although Rasmussen’s father insisted that police investigate Lazarus, who had been an officer for two years at the time of the murder, the case went cold until 2004, when the coroner was asked to retest DNA from a bite mark on the victim. Test results indicated the DNA belonged to a woman.

» RELATED: Jury Selection To Begin Monday In Stephanie Lazarus Trial

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