An illegal alien who has been living in the United States for four to seven years has been charged with first-degree murder in the death of 20-year-old college student Mollie Tibbetts after she went missing in her small town of Brooklyn, Iowa.

During a joint law enforcement press briefing on Tuesday, police officials revealed that Tibbetts’ body was found in a cornfield in the rural area of central Iowa and that 24-year-old illegal alien Cristhian Bahena-Rivera has been charged with murder in her death.

According to police, Rivera was the last person who saw Tibbetts jogging on the evening of July 18 in Brooklyn, Iowa, security camera footage reveals.

The illegal alien told police that Tibbetts was jogging on July 18 when he saw her. That is when he said he approached Tibbetts and started talking to her, even running alongside her and behind her.

Tibbetts, according to the illegal alien’s story, said he needed to get away from her or she would call the police. Tibbetts then started running and that’s when Rivera said he chased her down.

Police say Rivera told law enforcement that after this, he blacked out and eventually Tibbetts’ body was placed in a cornfield in the Brooklyn area. Police also said they first came into contact with the illegal alien yesterday.

Police officials said that security camera footage was “critical” in charging the illegal alien with the murder of Tibbetts.

Police have said they do not yet know a motive.

“For whatever reason, he chose to abduct her,” an Iowa official said.

On August 21, ICE lodged a detainer with the Poweshiek County Sheriff’s Office on Cristhian Bahena-Rivera, 24, an illegal alien from Mexico, after he was arrested on murder charges.

The Tibbetts’ family, who were visited by Vice President Mike Pence, have been notified of the discovery of Mollie’s body and the charges against the illegal alien.