According to the arrest affidavit, Rivera was "driving back and forth" near where Tibbetts was jogging on July 18. The affidavit said Rivera told investigators that he got out of the car and ran next to her, prompting Tibbetts to pull out her cellphone and threaten to call the police.
Rivera claimed he then blacked out "and doesn't remember anything after that until he came to at an intersection" in his car, the affidavit said, adding that Rivera realized that he had put Tibbetts in his trunk when he "noticed there was an ear piece from headphones in his lap." He said he then drove to a cornfield, dragged Tibbetts' bloody body to a "secluded location" and covered her body with corn stalks, according to the affidavit.
He later led police to the area, where they found a body matching Tibbetts' description, the affidavit said.
2. ICE officials lodged a federal immigration detainer for Rivera after his arrest. "That move means the agency has probable cause to believe he is subject to deportation," the AP reported.
Rivera's Facebook page said he is from Guayabillo in Guerrero, Mexico, according to the AP.
3. Authorities believe Rivera had been living in the Brooklyn, Iowa, area for as long as seven years. Officials said he "lived in a rural area and kept to himself," the AP reported.
4. He worked for Yarrabee Farms, a dairy farm owned by the family of prominent Iowa Republican Craig Lang. "This individual has worked at our farms for four years, was vetted through the government's E-Verify system, and was an employee in good standing," Yarrabee Farms said in a statement Tuesday, according to ABC News. "On Monday, the authorities visited our farm and talked to our employees. We have cooperated fully with their investigation."
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5. President Donald Trump spoke about Rivera's arrest Tuesday at a West Virginia rally. "You heard about today with the illegal alien coming in, very sadly, from Mexico and you saw what happened to that incredible, beautiful young woman," Trump said, according to the AP. "Should've never happened. Illegally in our country. We've had a huge impact, but the laws are so bad. The immigration laws are such a disgrace, we're getting them changed, but we have to get more Republicans. We have to get 'em."
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– The Associated Press contributed to this report.
What You Need to Know: Missing University of Iowa Student Mollie Tibbetts