HASTINGS — A 20-year-old University of Minnesota student who went missing last fall was stabbed to death in a Rosemount town house and her body dumped on the side of a rural road to try to cover up the crime, according to murder charges filed Friday against her ex-boyfriend and his girlfriend.

Prosecutors in Dakota County charged Shavelle Oscar Chavez-Nelson, 32, and Ashley Marie Conrade, 24, with second-degree intentional murder in the death of Anarae Schunk.

An autopsy found that Schunk’s throat and key arteries had been cut, and she had defensive wounds on her hands and arms. The medical examiner determined that she could not have lived for more than 20 seconds with her wounds.

“She fought for her life,” Dakota County Attorney James Backstrom said at a news conference.

According to the criminal complaints, Chavez-Nelson stabbed Schunk with a kitchen knife 22 times in September. Although Conrade repeatedly denied being involved in the killing, saying she had gone to bed early that night, the charges say Conrade’s blood was found on the kitchen floor, along with blood from Schunk and Nelson.

The charges also alleged that Conrade helped Nelson dispose of Schunk’s body, the Star Tribune reported.

Conrade’s version of what happened in her town house early on Sept. 22 changed repeatedly, according to the charges. But a week after the killing, when she was confronted with bloodstain evidence, Conrade admitted to police that when she returned home from work later that day she saw Schunk’s body on the kitchen floor.

At work that day, Conrade was seen with an injured finger and cuts on her palm and arm, the charges said.

Schunk, who had briefly dated Chavez-Nelson, had reconnected with him in an attempt to recover $5,000 she had loaned him, friends and family say.

Schunk was last seen with Chavez-Nelson, also known as Anthony Lee Nelson, and Conrade at a Burnsville bar on Sept. 22. That same night, Chavez-Nelson allegedly shot 23-year-old Palagor Jobi to death outside the bar. He is charged with first-degree premeditated murder in that killing and faces a jury trial in October. Conrade is charged with aiding an offender in that case.

Schunk returned with Nelson and Conrade to Conrade’s home after Jobi’s killing. Schunk was last seen alive by a friend of a neighbor of Conrade’s at about 3:30 a.m. Investigators believe Schunk was killed in the town house within the hour.

Conrade told police that at Nelson’s request, she helped him move a large plastic tub that was covered with a blanket. While she didn’t ask Nelson what was in the tub, she told police she knew it contained Schunk’s body, according to the complaints. Chavez-Nelson denied killing Schunk or knowing where she was.