TUCSON, Arizona — Authorities discovered DNA evidence unrelated to Nancy Guthrie at her home during a search on Wednesday, according to police sources. The Pima County Sheriff’s Office, working with the FBI, is analyzing the biological material in a lab as the search for the 84-year-old enters its 18th day.

Guthrie was last seen at her Tucson residence on January 31. Officials believe she was abducted around 2 a.m. the next morning. Family members reported her missing after she skipped a weekly virtual church service. Deputies arrived to find her gone, the front camera disconnected and blood on the door.

FBI agents recovered surveillance footage after 10 days. The video shows a masked man, about 5-foot-9 to 5-foot-10 with average build, disabling the camera. He carried a black backpack and wore black gloves, possibly revealing a ring underneath. Pima County Sheriff Chris Nanos addressed the ring detail Tuesday during an NBC News interview. “I look at the same photo you look at and I get it, I see it,” Nanos said. “I’m going to give that to my team. They’ll look at that. They’ll analyze it and we’ll see. Maybe, maybe it is.”

The reward for tips leading to Guthrie’s return or the suspect’s arrest and conviction started at $50,000. An anonymous donor added $100,000 on day 12 of the investigation. Milwaukee Crime Stoppers President Michael Hupy pledged another $100,000, though officials have not confirmed if he is the anonymous source. An extra $2,500 came via 88 Crime, pushing the total to $202,500, the sheriff’s office said Wednesday.

Recent leads have fizzled. A SWAT team raided a home near Guthrie’s on Saturday, searched a gray Range Rover and questioned its driver along with others. No arrests followed. Officers also found a glove near the property that seemed to match the suspect’s from video. Tests showed no CODIS match, the national DNA database for arrestees, Nanos said.

Media outlets received ransom notes. TMZ and two Arizona stations got demands for millions in Bitcoin. TMZ reported Wednesday on a new note seeking $6 million in another cryptocurrency. The outlet called it “sophisticated” and said it graphically threatened consequences for nonpayment. “It puts the media right in the middle of it,” TMZ stated.

Investigators explore cross-border possibilities. Sources told TMZ officials are coordinating with Mexican authorities. The sheriff’s office acknowledged the reports in a Wednesday release but declined further comment. Earlier talk of polygraph tests on suspects turned out to involve new hires only.

Nanos tempered expectations Tuesday. The probe could drag on for years, he said, but searchers will not quit. Asked if he believes Guthrie is alive, he replied, “They ask me, do I have proof of life? I ask them, is there proof of death?” The sheriff’s recent update noted multiple DNA profiles from the home evidence remain under analysis as part of the active case.