BROOKLYN, Iowa — Federal and state investigators are poring through "massive amounts of data" related to a missing University of Iowa student's digital footprint in an effort to track her whereabouts in the hours before she disappeared.

Iowa Division of Criminal Investigation spokesman Mitch Mortvedt said Wednesday that investigators believe they've "put together a pretty solid timeline" of what 20-year-old Mollie Tibbetts was doing before she was last seen jogging in her hometown of Brooklyn, Iowa, the evening of July 18. Mortvedt said he couldn't give details of those activities, citing the active investigation.

"We wish it could go faster, too," Mortvedt said of the investigation. "As you can imagine, it can be massive amounts of data we're going through."

Investigators with the FBI and Mortvedt's agency were combing through information returned from several search warrants issued to social media and fitness tracking companies, including Fitbit. Friends and family say Tibbetts, an avid runner, was usually wearing her Fitbit.

Other information comes from her cellphone provider, Instagram and Snapchat, Mortvedt said.

Tibbetts' boyfriend has said he received a Snapchat message from her the night of July 18 after she would have returned from her run.

Tibbetts 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.

Mortvedt said that with each passing day that Tibbetts isn't found, the possibility grows that she was taken against her will. But he added that investigators "haven't ruled anything out."