July 27 (UPI) -- Iowa police have ruled out the boyfriend of a missing college student as a suspect in her disappearance, investigators said.
Mollie Tibbets was last seen July 18 as she went for a jog. Boyfriend Dalton Jack, for whom she was house sitting the night she disappeared, is cooperating with investigators.
Iowa Division of Criminal Investigation spokesman Mitch Mortvedt said local, state and federal investigators are following several leads. Thursday, they searched a pig farm in Guernsey, Iowa, about 11 miles away from Tibbetts' last sighting in the town of Brooklyn.
"One avenue of thought is that if it wasn't a struggle, and we have found no signs of a struggle, then maybe it was someone she was familiar with," Mortvedt said. "But then the other avenue of thought is it could have been a stranger who simply overpowered her or tricked her. We just have very little to go on."
Mortvedt said investigators are interviewing several people who have a link to Tibbetts, but none have been taken into custody.
Investigators are also searching Tibbetts' Fitbit, a physical activity tracker, her social media accounts and other electronics to find clues. They have also searched multiple properties.
Mortvedt said investigators have a "pretty good timeline," but didn't give details.
Tuesday, FBI and state investigators took over the search, and authorities said it's beginning to appear she was abducted.