Celebrity Peterson Trial: Was Laci the Wrong Victim? The defense suggests that Scott Peterson's wife was killed in a case of mistaken identity By Ron Arias and Stephen M. Silverman Published on September 28, 2004 12:05 PM Share Tweet Pin Email A case of mistaken identity may have led to Laci Peterson’s death, defense attorney Mark Geragos suggested Monday in Scott Peterson’s double-murder trial, where he also revealed that the suspect was a repeat adulterer. In cross-examining Modesto, Calif., police detective Craig Grogan, Geragos probed the star prosecution witness about a look-alike identified as “Michelle D.” The woman, an assistant prosecutor in neighboring Merced who lived around the corner from the Petersons, had told police in the week after Laci went missing that the 28-year-old victim may have been mistaken for her, Grogan said. The petite brunette attorney had received repeated threats from a suspect she had been prosecuting for a violent crime, but Grogan said, while Modesto police had arranged to meet with this man, he did not show and there was no follow-up in the case. The detective also said that Laci’s mother, Sharon Rocha, told police that Laci had planned to walk her dog the morning of Dec. 24, 2002, the day that the defense contends she was abducted. Meanwhile prosecutors have asserted that Laci had stopped walking the dog weeks earlier at her doctor’s request and that Peterson had let the dog loose himself to make her disappearance seem like a kidnapping. Peterson, 31, stands accused of murdering the 8-months-pregnant Laci and their unborn son Conner in their Modesto home and dumping their remains into San Francisco Bay. He has pleaded not guilty. In yet another eyebrow-raising turn of events, Geragos painted Peterson as an experienced adulterer whose single affair with massage therapist Amber Frey would not have been motivation to kill Laci. Geragos told the jury that his client had previously cheated twice shortly after the couple were married Aug. 9, 1997. Regarding one of the incidences, detective Grogan testified that a woman who claimed to have had a five-month affair with Peterson had called police after Laci s disappearance. The woman, who was not identified in court, told police that Peterson never said he was married and that she only found out when she walked into Peterson s house and found him in bed with Laci. Bay Area criminal defense attorney and legal commentator Michael Cardoza said the defense team is attempting to set up an alternate version of events. “Geragos is basically asking the prosecution how thorough an investigation they did,” Cardoza says. “But then the prosecution opens up a very small opening, like a little tunnel, and Mark Geragos ends up driving a truck through it.” Judge Alfred Delucchi has said that prosecutors intend to wrap their case by Thursday, after 18 weeks of trial and more than 160 witnesses.