Genetic genealogy brings promise and challenges to the Nancy Guthrie case

Genetic genealogy brings promise and challenges to the Nancy Guthrie case Investigators are hopeful that some of the DNA that was found at Guthrie's home can be parsed and help point to a suspect in her disappearance. A Pima County Sheriff's vehicle sits in the driveway of the home of Nancy Guthrie, in the Tucson, Ariz. area, on Saturday. Joe Raedle / Getty Images Share Add NBC News to Google Feb. 22, 2026, 3:41 PM EST By Marlene Lenthang , Erin McLaughlin and Liz Kreutz Listen to this article with a free account 00:00 00:00 TUCSON, Ariz. — A Q-tip, a tissue and a pizza crust. To investigators, this seemingly innocuous trash was DNA-laden treasure, helping crack the cases of the University of Idaho murders , the Golden State Killer and the Gilgo Beach slayings , according to authorities, using a forensic tool called investigative genetic genealogy . Investigators in the Nancy Guthrie case hope that science can point to a suspect. But there are challenges. Guthrie, the 84-year-old mother of “TODAY” co-host Savannah Guthrie, was reported missing on Feb. 1 . It’s been three agonizing weeks since her disappearance, and authorities haven’t publicly identified a suspect or a person of interest. Officials have cleared the Guthrie family as potential suspects, Pima County Sheriff Chris Nanos said. Nanos, whose agency is leading the investigation along with federal and state partners, said last week that mixed and partial DNA was found at Guthrie’s home. Mixed DNA is a forensic sample that has more than one person’s genetic material. More coverage of Nancy Guthrie's disappearance What we know about the search for Guthrie Investigators press ahead nearly three weeks on from Guthrie’s disappearance Security video from Guthrie’s home offers potential clues for investigators Some of that DNA that was found at the home doesn’t belong to Guthrie, her family or anyone who worked at the residence, Nanos said. “We believe that we may have some DNA there that may be our suspect, but w...