Federal and state investigators hunting for the missing University of Iowa student have been reviewing data from her Fitbit and Snapchat in hopes of zeroing in on her location.

Mollie Tibbets, 20, was last seen jogging in Brooklyn, Iowa, on the evening of July 18. She was staying at her boyfriend’s home at the time of her disappearance. She was there to watch his dogs because he had a construction job about 100 miles northeast in Dubuque.

Authorities said they’ve “put together a pretty solid timeline” of what Tibbetts was doing prior to her disappearance. Friends and family say Tibbetts, an avid runner, was usually wearing her Fitbit.

“We’re checking gas stations and convenience stores and any location with easy access to a highway or the interstate,” Mitch Mortvedt, assistant director of field operations for the Iowa Division of Criminal Investigations, told The Gazette. “We’re asking questions and collecting surveillance footage and check it to see if Mollie was caught on camera or if there was someone in the area acting suspicious.”

Other information comes from her cellphone provider, Instagram and Snapchat, authorities said. Tibbetts’ boyfriend has said he received a Snapchat message from her after she would have returned from her run.

Tibbetts was born in San Francisco and lived in Oakland until she moved to Iowa with her mother when she was in second grade, the Des Moines Register reported. Her father, who lives in Fresno, reportedly flew to Iowa to assist the search.

Authorities said that with each passing day that Tibbetts isn’t found, the possibility grows that she was taken against her will.

Fox News' Edmund DeMarche, Bradford Betz and The Associated Press contributed to this report