To celebrate National DNA Day (April 25), we are highlighting this post from ScIU’s archives! It was originally published by Brittany Hood in January 2019.
Trigger warning: This post contains details of specific crimes that are related to sexual assault and murder.
In 1992, an 84-year-old grandmother was brutally assaulted and killed in California. For 25 years, the mystery of her death went unsolved — and her killer unapprehended — due to the lack of physical evidence to tie him to the crime. Twenty-five years later, police paid a visit to a pizza party, where they found sufficient evidence to arrest her murderer.
At first glance, the murder and the pizza party seem unrelated. However, there is a link: familial DNA. Familial DNA testing has traditionally been used for a multitude of reasons, such as to identify potential genetic predispositions and to structure family trees. However, with advancements in technology, law enforcement agencies are now utilizing familial DNA testing to identify serial killers. San Diego police found a familial DNA connection, suggesting that a biological brother was responsible for the 1992 rape and murder of 84-year-old Angela Kleinsorge. In order to confirm that the DNA belonged to the suspect, police went undercover to a birthday party and collected Lonnie Franklin’s leftover pizza crust and utensils. The DNA was a match, and Franklin was arrested a mere two hours later. He was eventually tied to ten murders and has since been suspected of more. He is now known as the “Grim Sleeper.”
This is not the first time that familial DNA has been used to identify a serial killer. In 2018, a man was identified as the “Golden State Killer” (a.k.a. the “East Area Rapist” or the “Original Night Stalker”) through a familial DNA match. He had gone undetected for 39 years. The DNA from crime scenes was entered into two online genealogical services to build a genetic profile and find relatives. Once Joseph DeAngelo was identified as a suspect in the Golden State murders, he was surveilled, and genetic material was collected from his car door and a tissue from his trash can outside. He was arrested the next day. DeAngelo, now a 79-year-old retired police officer, broke into the homes of four couples and two single women to rob them. He sexually assaulted the women, and all six of his victims were shot or beaten to death. He is suspected of up to 12 murders in total and at least 45 additional rapes.
Thanks to familial DNA testing, two serial killers who were flying under the radar for decades were apprehended. While this is a testament to the clear benefits of using familial DNA in criminal investigations, there are three arguments against the use of genealogy services for DNA identification.
Second, others claim that sometimes questionable methods are used to collect DNA evidence. In the Franklin case, the defense argued that he was not finished with his food and, therefore, the DNA was illegally obtained. Further, Franklin’s defense team explained that Franklin had a reasonable expectation that his trash would be thrown away, not collected, and that his trash and leftovers would not be able to be tied to him. The judge dismissed Franklin’s objection to the legality of DNA collection.
Third, the technique of matching DNA markers does not always lead to valid results, as large percentages of the population can share many specific DNA markers. This third argument emphasizes the risk of using genealogical services when there is a chance that the analysis could lead to misleading results. Now, this sort of error probably would not be too devastating if your family tree results were incorrect. But, it could be life altering for an individual who was wrongly arrested or convicted of a crime based on erroneous results. While the three arguments outlined above seem to be valid, at least on the surface, false arrest and/or conviction is the most significant negative impact to consider.
So, do the costs of familial DNA testing in criminal investigations outweigh the benefits? In my opinion, no. If a serial killer is apprehended and convicted, and justice is served as a result of familial DNA testing, law enforcement should use all of the resources available.
My question to you is, do you think it is ethically sound to use a genealogy website to identify potential serial killer suspects, or should law enforcement only rely on police databases? Should law enforcement use everything at their disposal to identify and apprehend serial killers?