The illegal alien accused of murdering 20-year-old college student Mollie Tibbetts allegedly stabbed her to death, an autopsy report reveals.

This week, law enforcement announced that Tibbetts’ body was found in a cornfield in her rural hometown of Brooklyn, Iowa after she was last seen jogging on July 18.

Illegal alien Cristhian Bahena-Rivera, a 24-year-old from Mexico, has been charged with first-degree murder in her death after police say he admitted to confronting and chasing down Tibbetts, eventually leaving her body in the cornfield. The illegal alien lived in a region of Iowa that was surrounded by sanctuary cities, as Breitbart News noted.

Now, following an autopsy report, the state medical examiner says Tibbetts died from “multiple sharp force injuries,” but did not explain exactly what was allegedly used by the illegal alien to murder the young woman.

The state medical examiner said additional results from the autopsy may reveal what was used to kill Tibbetts. The initial report did officially confirm the identity of Tibbetts.

As Breitbart News reported, Bahena-Rivera worked at Yarrabee Farms, a dairy farm in the region. The farm owner originally said that he used the E-Verify system to check whether Bahena-Rivera was an illegal alien, saying that he passed the screening. Later, the farm owner admitted that E-Verify was not used to check the immigration status of the illegal alien.

Bahena-Rivera is believed to have used a stolen or fake identity of an American citizen as he provided the farm with a fraudulent Social Security card.

The illegal alien, charged with first-degree murder in Tibbetts’ killing, has been living in the U.S. for four to seven years.

“On Aug. 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,” Immigration and Customs Enforcement (ICE) officials said in a statement to Breitbart News.

Police say Bahena-Rivera left Tibbetts’ body in a cornfield, placing corn stalks over her to hide her death. Foreign nationals, specifically illegal aliens, are often incentivized by employers to migrate to the Midwest to take low-wage farming and meatpacking jobs.

John Binder is a reporter for Breitbart News. Follow him on Twitter at @JxhnBinder.