Updated

The Latest on the discovery of a body believed to be that of 20-year-old missing Iowa college student Mollie Tibbetts (all times local):

5:15 p.m.

Court documents detail what a man charged with murder told investigators about the abduction and killing of Mollie Tibbetts.

An affidavit filed Tuesday says the 20-year-old Tibbetts was running on July 18 in a rural area near Brooklyn, in central Iowa, when a car driven by Cristhian Bahena Rivera approached her.

During questioning Monday, Rivera acknowledged making contact with Tibbetts, first by pursuing her in his car and then getting out and running beside her.

Rivera told investigators he became angry when Tibbetts showed a cell phone and threatened to call police. He says he panicked and then "blocked" his memory. He says he does not recall what happened but found an earpiece from headphones in his lap and realized he'd put Tibbetts' in his trunk.

He opened the trunk and noticed blood on the side of her head.

The affidavit says he carried Tibbetts' body to a cornfield and covered her with corn stalks. When he was questioned by authorities, he led investigators to the site.

Rivera has been charged with first-degree murder.

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4:50 p.m.

A federal agency says a man charged with killing an Iowa college student is a citizen of Mexico who was in the country illegally.

Immigration and Customs Enforcement released a statement Tuesday stating that it had "lodged a detainer" with the Poweshiek County sheriff's office to hold 24-year-old Cristhian Bahena Rivera after he was charged with first-degree murder.

At a news conference, Rick Rahn, special agent in charge with the Iowa Division of Criminal Investigation, said Rivera had been living in the area for four to seven years.

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This version of the Latest corrects the spelling of the first name of the man charged to Cristhian.

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4:20 p.m.

Police say a man in the country illegally has been charged with murder in the death of Iowa college student Mollie Tibbetts.

A charge of 1st degree murder has been filed against 24-year-old Cristhian Bahena Rivera. If convicted, the charge carries a mandatory sentence of life in prison.

Investigators say they used surveillance video in tracking down Rivera. The video showed Tibbetts jogging in a rural area near her hometown of Brooklyn as well as Rivera's car.

Police had searched the area but noted her body was found in a field, covered with corn stalks.

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3:55 p.m.

Authorities say they are holding a suspect in the death of Iowa college student Mollie Tibbetts, and he is being held on a federal immigration detainer.

Mitch Mortvedt, an assistant director of the state Division of Criminal Investigations, says Tuesday that authorities are holding a suspect and will release more details during a 4 p.m. news conference.

Earlier Tuesday, investigators announced a body believed to be Tibbetts was found in rural Poweshiek County.

Tibbetts, a 20-year-old student at the University of Iowa, has been missing since July 18.

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9:45 a.m.

Police say a body believed to be that of 20-year-old college student Mollie Tibbetts has been discovered in a rural area near where she went missing last month.

The Iowa Division of Criminal Investigation says the body was found Tuesday morning in rural Poweshiek County, which includes Tibbetts' hometown of Brooklyn, Iowa.

The agency called a 4 p.m. news conference to provide an update on the search for Tibbetts, saying investigators were working to confirm the identity of the body.

Tibbetts has been missing since July 18, when she was last seen jogging through the streets of Brooklyn.

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8:30 a.m.

Investigators believe they have found the body of Mollie Tibbetts, a University of Iowa student who has been missing for more than a month.

The 20-year-old woman was last seen July 18, jogging in her hometown of Brooklyn in central Iowa.

Greg Willey, the vice president of Crime Stoppers of Central Iowa, says a body found Tuesday is believed to be Tibbetts.

No information has been released about where the body was found.

Willey says a nearly $400,000 reward fund for her discovery will now become a reward for information leading to the capture of any suspects.

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Read the full story here: https://apnews.com/c40d14e3d9dd45faa7e23775404ad256