This audio podcast from the National Institute of Justice's (NIJ's) Just Science series consists of an interview with Kimberly Meza, a DNA analyst with the Mesa Police Department's (Arizona) crime lab, in which she reviews the crime-scene evidence and subsequent crime lab procedures from a killing, with a focus on the DNA from a blood spatter and a critical factor in finding a DNA match to the killer.
The interview begins with a review of Meza's educational and professional background, including her role as both a crime-scene analyst and DNA analyst. The case at issue in the interview involved the stabbing death of a mentally challenged young man who was living in an apartment under the financial support of his father. The father found his son dead in the apartment and reported it to the police. The death was due to a stabbing. The initial challenge for the crime lab was to determine whether any of the blood found at the scene belonged to the killer. One of the blood spatters at the scene was determined to be an unknown person, possibly the killer. A search of CODIS found no match. For 6 months, Meza checked all DNA samples analyzed by the crime lab to see if there were any matches. In the sixth month, the analysis of a sexual assault kit produced a DNA match. It was traced to the ex-boyfriend of a woman who reported being sexually assaulted by him. He eventually confessed to the killing of the stabbing victim. The circumstances of the killing and lessons learned from this case are discussed.