A first-degree murder charge was filed on Tuesday against a 24-year-old man in the case of missing Iowa jogger Mollie Tibbetts, state officials said Tuesday.
The suspect, Christian Rivera, is an undocumented immigrant who lives in the rural area where the college student vanished one month ago, according to the Iowa Division of Criminal Investigation.
A body recovered Tuesday morning in a farm field is believed to be Tibbetts, officials said, but the identity has not yet been confirmed.
(MORE: Dad of missing Iowa jogger Mollie Tibbetts 'reluctantly' returns home to California as investigation continues)
Rivera led authorities to Tibbetts' body, according to officials.
Tibbetts, a 20-year-old rising sophomore at the University of Iowa, disappeared the evening of July 18 while jogging in the rural farming town of Brooklyn, a close-knit community of about 1,500 residents.
The disappearance was completely out of character for her, Mitch Mortvedt, assistant director of field operations for the Iowa Division of Criminal Investigations, said at a news conference last week. The state agency formed a task force with the FBI and the Poweshiek County Sheriff's Office to investigate.
Laura Calderwood, Tibbetts' mother, told ABC News last month there are "no words to describe how you feel when you don't know where or how your child is," calling it "excruciating."
One of Tibbetts' brothers, Scott Tibbetts, told ABC News last month he believed his sister was "fighting her best to get back home."
"I think the best thing, personally, to hang onto hope is ... she's a better fighter than anyone I know," he said. "So whatever situation she's in, it's not like she's going to sit there and give up."