The FBI joins the search for students at the University of Iowa amid new fears that something happened 'against their will'

FBI and state investigators on Tuesday they have assumed the search for a student at the University of Iowa who has been missing for almost a week and the authorities said that he is "leaning more and more towards something that happens against his will".

Volunteers seeking Mollie Tibbetts, 20, of Brooklyn, Iowa, were suspended this week when the FBI and state investigators took over, said Mitchie Tibvedt, spokesman for the Division. of Criminal Investigation of Iowa.

We are still asking for help of the public … We would like to obtain any information we can. The more eyes and ears we have, the better.

– Mitch Mortvedt

Mortvedt said that officials "are leaning more and more toward something that it happens against his will "

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Tibbetts was taking care of dogs at his boyfriend's house Last Wednesday, KCRG-TV reported. According to reports, her boyfriend, Dalton Jack, was 100 miles away at a construction job.

A neighbor reported seeing her go for a run that night. Jack told the station that he received a picture of Snapchat from her on Wednesday night, after she had returned home from her trot.

When he sent her a text message on Thursday morning, she said she did not respond, so she met with friends and family members.

FBI and Iowa investigators are now focusing on the areas around Brooklyn that Tibbetts frequented. The FBI is also studying Tibbett's online history and the use of the cell phone application in an effort to identify where it might be, Mortvedt said.

Tibbetts was born in San Francisco and lived in Oakland until he moved to Iowa with his mother when she was in second grade, reported the Des Moines Registry. According to reports, his father, who lives in Fresno, flew to Iowa to help with the search.

Dozens of volunteers in Brooklyn have searched for fields around Tibbetts house, as well as of Jack. They also covered the area with posters, t-shirts and posters lost in an effort to find it.

Tibbetts aunt, Kim Calderwood of Brooklyn, told the Des Moines Registry that the Tibbetts family is frustrated by the lack of progress in the search.

"We are destroying our brains, thinking about what we can think to tell the researchers" , He said. "The worst thing is to want to fix something that can not be fixed"

The Associated Press contributed to this report.