On Tuesday, investigators from the FBI and the state took over the search for a student from the University of Iowa, who has been missing for nearly a week, and the authorities said that they are "more and more on something against their will." ,  Volunteers looking for Mollie Tibbetts, 20, from Brooklyn, Iowa, were recalled this week when the FBI and state investigators took command, Mitch Mortvedt, a spokesman for the Iowa Criminal Investigation Department.
We are still asking for the help of the public … We would like to receive all the information we can. The more eyes and ears we have, the better.
Mortvedt said that officials were increasingly turning against something they did against their will.
Tibbetts sat with her dog at her friend's house last Wednesday, KCRG-TV reported. Her friend, Dalton Jack, is said to have been 100 miles away on a construction job.
A neighbor reported seeing her jogging that night. Jack told the station that he had a snapchat photo of her late Wednesday night after she returned from her jogging home.
When he texted her on Thursday morning, he said she did not answer, so he got her friends and family.
FBI and Iowa investigators are now focusing on areas around Brooklyn known to Tibbetts. The FBI is also investigating Tibbetts online story and using the mobile app to find out where it might be, Mortvedt said.
Dozens of Brooklyn volunteers have searched fields around Tibbetts house and Jacks. They also covered the area with missing posters, T-shirts and poster requests to find them.
Tibbetts aunt, Kim Calderwood of Brooklyn, told the Des Moines Register that Tibbetts' family was frustrated by the lack of progress in the search.
"We break our brains, thinking, what can we think of the investigators," she said. "It's the worst thing to want to fix something you can not fix."
The Associated Press has contributed to this report.