Thousands of immigrants have died crossing the southern U.S. border. Many are never identified, leaving their loved ones to speculate about their fate.

Lori Baker, an associate professor of anthropology at Baylor University in Texas, volunteers on behalf of those families, using DNA samples to identify bodies buried in unmarked graves. The 44-year-old sat down for StoryCorps with her husband, Erich, and talked about what inspired her work. Baker recalled visiting a sheriff's office, where she noticed a disturbing object on his desk.

"It was the skull of a younger person, and [the sheriff] was using it as a pencil holder," Baker said. "He had pens and pencils in the eye socket of this person. So that's when I decided something had to be done."

Baker travels to cemeteries along the U.S.-Mexico border, taking DNA samples from unidentified bodies. Then she cross-references those samples with reports filed by families of immigrants who went missing. The goal, she said, is "to find one little thing that might connect to the case that you're working on."

Identifying a body helps family members find resolution, Baker said. "But the families are going to know the horrible things that happened to their loved one," she said. "They die of heat stroke. ... And it's really overwhelming when you're holding them in your hands and you see the blisters that are on the feet of these individuals."

Baker remembers the first time she identified a body. It was a woman who lived with her mother and struggled to support her two young daughters. The woman decided to migrate to the U.S. to work and send money back to care for her children. But when she was injured during the trip, her smugglers left her behind.

"I thought, 'I gotta find out from that mom if it would have been better just not to know — thinking that maybe she lived and would come home someday,' " Baker said. "And she said, 'No. The hope eats you alive every day.' And now they say they are blessed because they're able to lay flowers on her grave."

Baker told Erich, who is an assistant professor in bioinformatics at Baylor, that her job hasn't gotten any easier with time. "I would love not to do this anymore, but I don't think I have it in me not to," she says. "Especially when we have an 11-year-old child and I know we probably won't figure out who he is and his mom's probably grieving somewhere. ... I don't know that I'll ever get over it if we don't figure out who he is."

Produced for Morning Edition by Jasmyn Belcher Morris.

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