DNA Is Now Solving Decades-Old Newborn Killings
By: Emily Mullin
Tags: Crime, Science, Genetics, Privacy, Data Privacy

DNA Is Now Solving Decades-Old Newborn Killings

Genealogy databases are leading police to mothers who killed their babies

On May 15, 1988, two children were playing near a creek in Northern California’s sunny Castro Valley when they made a disturbing discovery. At the top of an embankment along the creek, they found a bag containing the body of a newborn baby boy. He was swaddled in a light blue, adult-sized Garfield T-shirt. An autopsy later determined that the baby died by homicide. The mother, who investigators considered a suspect, could not be found.

The investigation turned up no viable leads. No one seemed to have any information about who the mother could be. In July 1988, a local church organized a funeral for the nameless infant, and 200 members of the community attended. Church leaders named the baby Richard Jayson Terrance Rein, while police referred to him as Baby John Doe. The case went cold for 17 years.

Then, in 2019, Alameda County police uploaded the baby’s DNA profile to an online genealogy database, which allows people to find relatives based on matching DNA. This enabled the police to trace the baby’s relatives to the mother, Lesa Lopez, now a 52-year-old grandmother living in Salida, California, about an hour east of Castro Valley. When police visited Lopez at her home in July, she admitted that she was the mother of the baby, who’d been born when Lopez was 20 years old. She told investigators that she had hidden the pregnancy from her family and friends.

Few details about Lopez have been made public, but her Facebook photos belie the notion of a cold-blooded killer. Instead, Lopez’s profile reflects a love of animals, the band Kiss, and spending time with her family and friends.

The investigative technique police used, known as forensic genetic genealogy, combines information in consumer DNA databases with traditional genealogy. Its use has taken off in recent years after law enforcement used it in 2018 to identify Joseph James DeAngelo as the Golden State Killer, who was sentenced to multiple life sentences in August for committing at least 13 murders and 50 rapes across California in the 1970s and 1980s.

Since DeAngelo’s 2018 arrest, genetic genealogy has solved more than 200 U.S. homicides and sexual assault cases, many of which had long gone cold. Now, police are increasingly using the technique to identify the mothers of infants who were killed or abandoned years ago. In 2020, police across the country announced that they solved several such “Baby Doe” cases with genetic genealogy, including one this month in Michigan, where a 41-year-old woman was charged with murder in the deaths of her twin newborn sons in 2003.

But some feel that its use in identifying the mothers of these newborns takes the technique too far. Research suggests that most mothers who murder babies within the first day of birth — known as neonaticide — do not premeditate the crime and aren’t violent. Instead, these girls and women, who are often unmarried, scared, and without the resources to care for a child, act out of impulsive panic after they deliver the baby. Experts estimate that a few hundred neonaticides occur in the United States each year, but the true incidence is unknown.

On one hand, genetic genealogy is a way to bring justice to the babies who never got the chance to live out their lives. But the growing use of the technique could also mean imprisoning women who may pose no threat to society.

“If you develop the atom bomb, do you have to drop it?” says Michelle Oberman, a law professor at Santa Clara University who has written two books about mothers who kill their children. “It’s really tempting, once you have the technology, to run through every cold case that you’ve ever had and see what turns up.”