Familial DNA searches to home in on crime suspects is gaining ground, the Los Angeles Times reports.
In cases where investigators have been unable to uncover a suspect — such as in the Grim Sleeper serial killer case in Los Angeles — they've run suspect's DNA through databases, looking not for a full match, but a partial one. In that way, they've identified possible relatives of the suspect that can then lead them to the suspect himself. For instance, in the Grim Sleeper case, in which nine women and a teenage girl were killed over the course of 20 years in South LA, investigators traced DNA evidence to a man who was arrested on gun and charges and then zeroed in on that man's father, Lonnie Franklin, Jr., who lived near where the bodies were found.
Critics of familial searches argue that it constitutes an unreasonable search and will disproportionately affect African Americans and Latinos, as they are over-represented in law enforcement DNA databases. But some, the LA Times says, have come around to the approach, as it's been used sparingly. "If it's helping us solve big cases," Jennifer Mnookin, the dean of the University of California, Los Angeles, Law School, tells the LA Times, "it seems like a worthwhile trade-off."
Such searches are becoming more common, as eight states have protocols in places for their use, while other states rely on it more informally, the LA Times adds. Still, it notes that Maryland and the District of Columbia don't allow familial searches. "It is a slippery slope," says Steve Mercer from the Maryland Office of the Public Defender."