By Adriana Diaz CBS News August 21, 2018, 6:39 PM Mollie Tibbetts case: Suspect led investigators to missing college student's body

BROOKLYN, Iowa — A man in the U.S. illegally has been charged with the murder of Mollie Tibbetts, the college student who went missing nearly a month ago. Investigators recovered a body believed to be hers on Tuesday.

Investigators charged Cristhian Bahena Rivera with the abduction and murder of Tibbetts. The 20-year-old disappeared July 18 after going on her daily jog.

Cristhian Bahena Rivera

Iowa Department of Public Safety

Surveillance video lead investigators to Rivera, who took them to Mollie's body, just miles from Brooklyn, Iowa. Investigators wouldn't release a motive, or any information about how Tibbetts was killed. But they said Rivera, who worked in the area, had lived in Iowa for three to four years.

More than a dozen FBI agents helped in the search. They used location data from the Fitbit she was wearing, and poured over hundreds of leads.

Earlier this month, her parents told CBS News their daughter had so much to look forward to, including her first trip abroad.

"She couldn't have been any happier, this was the summer of a lifetime," said Robert Tibbetts, her father. "She was the best man at my wedding. She's had an incredible summer, she was as happy as i'd ever seen her."

"I think Mollie's smile has grabbed the collective soul of this world," said Laura Calderwood, Mollie's mother.

For many in the small town, the pain of Tibbitts disappearance will endure.

CBS News asked investigators if there was any sign of a struggle. They wouldn't comment until the autopsy results come in. The autopsy is scheduled for tomorrow, but results could take weeks. In the affidavit, the suspect said he remembers being in his car the next morning and finding Tibbetts in his trunk, bleeding from her head.

© 2018 CBS Interactive Inc. All Rights Reserved. cristhian-bahena-rivera.png