The family of a 20-year-old college student who disappeared in Iowa two weeks ago is now offering $172,000 to help bring her home. 

The mother of Mollie Tibbetts believes her daughter may have been abducted on July 18 and begged her possible kidnappers to let her go. 

"We believe that Mollie is still alive, and if someone has abducted her, we are pleading with you to please release her," Tibbetts' mother, Laura Calderwood, said during a Thursday morning press conference.

Tibbetts disappeared after going for a jog near her boyfriend’s home in Brooklyn, Iowa.

Police said a witness in Missouri reported a possible sighting of Tibbetts at a local truck stop on July 26. An Iowa task force is investigating.

Calderwood said she still feel’s her daughter’s presence.

"Sometimes I just feel her sitting on my shoulder," she said. "Mollie was an incredibly strong young woman, and I don't know that I have the strength in me but Mollie is lending me her strength every day, every night."

Greg Willey of Crime Stoppers of Central Iowa said the reward will continue to grow. Donations can be made on the Crime Stoppers website, he noted.

Anyone with information is encouraged to call Crime Stoppers of Central Iowa at 1-800-452-1111.

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