Ashley Conrade, the girlfriend of the man accused of killing University of Minnesota student Anarae Schunk, pleaded guilty Friday to aiding an offender after the fact.

As part of the agreement, she will cooperate with prosecutors and testify against Shavelle Chavez-Nelson, who is charged with first-degree murder in connection with Schunk's death. The plea agreement calls for Conrade, 25, to be sentenced to 15 years in prison — once the case against Chavez-Nelson is resolved.

Conrade also pleaded guilty Friday to aiding an offender after the fact in the death of Palagor (Paul) Jobi. Chavez-Nelson, who was convicted in September of killing Jobi, is serving life in prison for that murder.

Investigators say Schunk, 20, went with Chavez-Nelson, 32, and his girlfriend, Conrade, to Nina's Bar & Grill in Burnsville around 12:30 a.m. on Sept. 22, 2013. At closing time, Chavez-Nelson got into a fight with Jobi in the parking lot. Jobi, 23, of Savage, was shot dead.

After the shooting, the three returned to Conrade's townhouse — where Schunk was last seen alive. Investigators believe she was killed in the kitchen between 3:30 and 4:30 a.m.

Police said Conrade gave multiple versions of events that unfolded that morning. But in each, Conrade denied killing Schunk and insisted she didn't know who had killed her, how Schunk died or where she could be found.

Conrade told police she went to sleep when they returned home and then rose early for work the next day. A co-worker noticed she had an injured finger, a cut on her palm and a cut on her arm.

A full week had gone by before Conrade admitted she had seen Schunk's body lying on the kitchen floor when she returned home from work on Sept. 22, authorities said. The confession came after police confronted her with blood evidence found in her home.

Conrade told police she assisted Chavez-Nelson in disposing of the body and cleaning the kitchen with bleach. Schunk was found Sept. 30 in a roadside ditch near Lonsdale, Minn. Her naked body was riddled with 22 stab wounds.

Conrade was indicted in July on first-degree premeditated murder and second-degree murder in connection with Schunk's death.

"This plea agreement was offered after additional evidence in the investigation of the death of Anarae Schunk was uncovered following the issuance of the indictment against Conrade," Dakota County Attorney James Backstrom said in a written statement. Backstrom declined to comment further until Chavez-Nelson's case is resolved.

Chavez-Nelson's next court appearance is set for March 20 at 9 a.m. in Hastings.

Schunk met Chavez-Nelson at a bus stop in the summer of 2012. He told her he was a hedge-fund manager. Even after she learned about his real background, she believed she could help him turn his life around, her family has previously said. Schunk and Chavez-Nelson dated during the summer of 2012.

On the night of Schunk's death, Conrade became jealous when she saw Chavez-Nelson place his arm around Schunk as they were walking into the bar, according to the criminal complaint.

Conrade later told police, "I was pissed that he like put his arm around another girl in front of my face."

Reporter Pat Pheifer contributed to this report.