Nancy Guthrie, the missing 84-year-old mother of “Today” show host Savannah Guthrie, did not leave home on her own, and she’s at risk of dying if she doesn’t get her medication in the next 24 hours, authorities said Monday.

“We believe ... that we do, in fact, have a crime scene, that we do in fact have a crime,” Sheriff Chris Nanos of Arizona’s Pima County told reporters a day after officers searched her home near Tucson.

Guthrie’s family contacted authorities Sunday around noon to report her missing after a member of her church alerted them she wasn’t in attendance at services. She was last seen on Saturday.

“She did not leave on her own. We know that,” Nanos said, noting that because of her very limited mobility, investigators “know she didn’t just walk out of there.” At this time, he couldn’t provide any more information about how authorities concluded a crime had taken place, just that “there were circumstances on scene that ... are suspicious in nature.”

Time is of the essence due to Guthrie’s medical needs, the sheriff emphasized. If she doesn’t take one of her medications in the next 24 hours, he said, “it could be fatal.”