Investigators in Iowa have zeroed in on missing jogger Mollie Tibbetts' digital footprint, including her Fitbit -- which can capture GPS data -- as they work to solve her mysterious disappearance. 
 
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 Tibbetts, a 20-year-old rising sophomore at the University of Iowa, went jogging the evening of July 18 in her rural town of Brooklyn, Iowa, and never returned. She was reported missing the next day. 
 
 "She probably has on her Fitbit because she never takes it off," her boyfriend, Dalton Jack, said. "She uses it for the sleep tracker and for all her runs." 
 
 Facebook 
 
 Jack last saw his girlfriend July 16, he said. The next day, he went to Dubuque for his job at a construction company, while Tibbetts stayed at his house alone and watched his dogs, Jack said. 
 
 Going for an evening run, he added, was part of her regular routine. 
 
 Poweshiek County Sheriffs Office 
 
 "For a 20-year-old to go missing and completely kind of fall off the grid as far as social media, cell phone, banking activity, that kind of thing -- it’s obviously a very suspicious and very serious matter," Mitch Mortvedt, assistant director of field operations for the Iowa Division of Criminal Investigations, said. 
 
 KCRG 
 
 "She’s very well-connected through social media, cellphone, exercise equipment," Mortvedt said, "so we are trying to use that, obviously, to our advantage to gain any information that we can." 
 
 Poweshiek County Sheriff Thomas Kriegel added: "We do believe that there's going to be some useful information [from the Fitbit data] but [we are] not willing to share that.” 
 
 Fitbit Inc., which makes the activity trackers, declined to comment. 
 
 Rob Hess/ABC News 
 
 Police are also looking at surveillance video from businesses in town that are along the route Tibbetts she usually jogs, the sheriff said. 
 
 "She was kind of a creature of habit," Mortvedt, of the state Division of Criminal Investigations, said. "And about the same time every evening she’d go for a run during daylight hours; well before dusk or dark, and she was seen Wednesday evening on one of her normal routes." 
 
 Poweshiek County Sheriffs Office 
 
 In this close-knit farming community of about 1,500 people, everyone knows everyone, Sheriff Kriegel said. But the rural area makes the search difficult. 
 
 "We're surrounded by farm ground: corn and soybeans. Right now the corn is probably eight, nine feet tall. The only way you can search it is basically walk down every other row," he said. "It's difficult. Even the planes flying over have a difficulty looking down in the corn rows." 
 
 KCRG 
 
 KCRG 
 
 Meanwhile, Tibbetts' family is searching every field and every creek in town as they anxiously hope for answers. 
 
 One of Tibbetts' brothers, Scott Tibbetts, said he believes his sister is "fighting her best to get back home." 
 
 "She's a better fighter than anyone I know," Scott Tibbetts said. "So whatever situation she's in, it's not like she's going to sit there and give up." 
 
 Mollie Tibbetts' boyfriend and brothers are not suspects, Kriegel said. 
 
 Anyone with information can call the Poweshiek County Sheriff's Office at 641-623-5679. 
 
 ABC News' Alex Perez, Andy Fies, Rob Hess and Amanda McMaster contributed to this report. ||||| The reward for information leading to the discovery of a missing University of Iowa student has doubled, thanks to an electric utility company. Mollie Tibbetts went missing in mid-July and, despite continued searching, has not been found. 
 
 Tibbetts, 20, went missing from her hometown of Brooklyn, Iowa, on July 18, while she was while dog-sitting for her boyfriend’s brother. Kim Calderwood, Tibbetts's aunt, previously told Newsweek a search for the student began when she didn't show up for her summer job as a camp counselor the next day. 
 
 
 
 TIP Rural Electric Cooperative of Brooklyn, Iowa, announced on Saturday that the company will match the $1,000 reward for information about Tibbetts’s disappearance put forth by Crimes Stoppers of Central Iowa for a total of $2,000 for any information leading to an arrest in the case or the discovery of the student, KCCI reported. Jon Miles, the general manager of the company, told Newsweek that the decision was made at a board meeting last week after learning about Tibbetts's disappearance. 
 
 Ames Police Department/Screenshot 
 
 "Our board of directors expressed concern over the case and wanted to step up to help," said Miles. "We hope the reward will nudge someone forward with information to help solve the case. Our hearts go out to the family." 
 
 The Iowa Department of Public Safety’s Division of Criminal Investigation (DCI) said in a statement on Friday that they have not identified a suspect in the case and are working with the Poweshiek County Sheriff’s Office, the Federal Bureau of Investigation and other local law enforcement agencies to help find Tibbetts. 
 
 Investigators involved in the search announced on Thursday they have executed search warrants for Tibbetts’s Fitbit, Snapchat, Instagram and Facebook accounts in hopes of finding information that could help locate her. Authorities told CBS News that Tibbetts sent a Snapchat to her boyfriend, Jack Dolton, around 10 p.m. It is unclear if Tibbett went missing the night of July 18 or the morning of July 19. 
 
 
 
 Mitch Mortvedt, assistant director of the Iowa DCI, told The Des Moines Register on Thursday that investigators were looking into the areas she frequently jogged because she was a “creature of habit” who stuck to her routine. 
 
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 “We haven’t ruled anything out,” Mortvedt told the publication. “But it’s been a week so it’s more and more suspicious to us." 
 
 Authorities told Fox News they have searched cornfields and a pig farm located nearby her boyfriend’s home, but have not found her. Rick Rahn, a special agent in charge at DCI, told Fox News on Friday that other sites and areas will be searched during the investigation. 
 
 
 
 “We’re looking at anybody and everybody that would lead us to locating her," Rahn said. 
 
 Anyone with information about Tibbetts’s disappearance should email the Poweshiek Sheriff's Office at tips@poweshieksheriff.com or call (641) 623-5679. 
 
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– Mollie Tibbetts is still missing, nearly two weeks after the 20-year-old University of Iowa student went on a late-night run and disappeared, and her father is pleading for the public's help finding her. "What we need is for people to tell their friends and neighbors that if they saw anything that seemed even remotely out of the ordinary to call the authorities and they will run that down," her father, Rob, tells Good Morning America. "We just need people to think—because somebody knows something and they don’t even know it’s important." The FBI has joined the search for Tibbetts, and police are hoping the FitBit she reportedly "never takes off" might lend some clues. The reward for information leading to her discovery has doubled to $2,000, Newsweek reports. When she disappeared, Tibbetts was dogsitting at the home of her longtime boyfriend, Dalton Jack, while he was more than 100 miles away, working a construction job. (He is not a suspect in the case.) She sent him a Snapchat photo that appeared to have been taken indoors the evening of July 18; the next morning, a friend of hers from work alerted Jack she had not come in to work or called, and he knew something wasn't right. Family members tell KCCI that evidence shows Tibbetts was doing homework on her computer late in the evening on July 18; while authorities won't comment on a specific timeline, family members say this opens up the possibility that she returned to the home after her run. She was last seen while out running.