Mollie Tibbetts, the Iowa college student whose body was found in a cornfield earlier this week, was stabbed to death, according to preliminary autopsy results.
"The State Medical Examiner determined that the manner of death was homicide resulting from multiple sharp force injuries," the Division of Criminal Investigation said in a release Thursday.
Sharp force injuries are described as an attack using a knife or other type of sharp-edged object.
Dennis Klein, the state's medical examiner, declined to provide additional details about Tibbetts' injuries in an interview with Fox News. Klein said her remains would be investigated further to determine additional findings.
Authorities charged Cristhian Bahena Rivera, 24, with first-degree murder Tuesday after he led investigators to her body in a cornfield outside of Brooklyn, Iowa, according to the arrest warrant affidavit obtained by TheBlaze.
Rivera is reportedly an illegal immigrant from Mexico who worked at a dairy farm and lived in the Brooklyn area several years. Immigration and Customs Enforcement agents helped local and state authorities track down the suspect whose vehicle was captured on video surveillance cameras.
The 20-year-old Tibbetts disappeared after going for an evening jog on July 18 in Brooklyn, Iowa. She was a psychology major at the University of Iowa.
The suspect told authorities that he started following Tibbetts in his Chevy Malibu and eventually parked the car, according to the arrest warrant affidavit.
Then he got out and started running after the young woman.
Rivera said that Tibbetts told him she was going to call the police. He told police that he "panicked and got mad." Then he said he "blocked" his "memory" until he realized he had put her in the trunk of his car.
Rivera said he drove to the cornfield where he dumped her body and covered it with corn stalks.
Rivera's manager at Yarrabee Farms said the suspect showed up to work every day following Tibbetts' disappearance and that he showed no signs of unusual behavior during that time.
“Our employee is not who he said he was,” manager Dane Lang said during a news conference. “This was shocking to us.”
Rivera is being held on $5 million bond. His preliminary hearing is scheduled for Aug. 31.