Her book, “Crime Scene Staging Dynamics in Homicide Cases,” an exploration of the topic, was published last year by CRC Press. The book revisits criminal case histories stretching back to the story of Cain and Abel (“Am I my brother’s keeper?”), to Shakespeare’s version of the life of Macbeth (“Out, damned spot!”), through to high-profile homicides such as Susan Smith drowning her two sons in 1994 amid a bogus kidnapping story, and the brutal slaying of Laci Peterson by her husband Scott Peterson in 2002.
Pettler’s main focus is “intimicide”—a crime of passion killing between intimate partners. Though each case is unique, the most common intimicides involve males killing females, and then making the scene look like a suicide or a disappearance. Pettler’s book looks at the staged crime scene, and offers a methodology to reason out the totality of evidence, from the analysis of the initial 911 call, to lividity and rigor mortis offering clues about body positioning, and ballistics to verify whether the angle of a gunshot could be self-inflicted or not.
But the psychology and circumstantial evidence can also help guide an investigation, Pettler said. She advocates for analyzing the “victimology” of the deceased, as much as the physical forensic traces.
“America is hyper focused on physical evidence. Investigators can get tunnel vision on the forensic evidence,” she said. “But the crime scene does not always put the weapon in the hands of the offender.”
Pettler pointed to the case of Betty Lafon Neumar as just one possible example of how a crafty killer can get rid of a partner. Pettler was the district attorney’s investigator on a cold case task force that determined the deaths of Neumar’s five husbands and one son was suspicious. Then a 76-year-old grandmother, she was arrested in 2008 for the 1986 death of her fourth husband, Harold Gentry. But, Neumar died before she could stand trial, so she was never convicted of anything.
Whether it’s slowly poisoning a husband, or shooting a wife and then putting the pistol in her hand, killers have come to realize that they can try to distort the forensic science to give them a chance at getting away with murder. The “CSI Effect” is well-known: popular depictions of criminal investigations on TV and in the media raise the expectations prosecutors have to meet, sometimes to an impossibly high standard.