Nathan Middleton, 30, of Evansville pleaded guilty Thursday in Rock County to charges of hiding a corpse and mutilating a corpse.
As part of a plea agreement, a charge of attempted escape was dismissed but read into the record. Middleton was accused of plotting to escape from his jail cell by allegedly asking his mother to blow a hole in the Rock County Jail wall.
District Attorney David O'Leary said he will argue for the maximum sentences, a combined 32.5 years in prison on the two charges, when Middleton is sentenced May 21.
Investigators suspect Middleton is responsible for the death of 18-year-old Aprina Paul, of Fitchburg, but have not been able to prove it.
According to the complaint, Middleton said he found Paul dead in his bed Oct. 28 after having sex and doing drugs with her the previous night. The complaint said they met after Paul responded to Middleton's ad on Craigslist.
O'Leary said the defense asked if the prosecution would agree not to file any future charges as a result of Paul's death, "and I told them, absolutely not."
"If and when we can prove the cause of death, we would be filing charges related to the death of Aprina," O'Leary said.
Sheriff Bob Spoden said recently that he had little hope that forensic tests of burned bone fragments would yield any evidence of how Paul died.
Test results still pending might confirm that the fragments are indeed those of Paul, Spoden said, although the family has for some time accepted that she died at Middleton's home.
According to the complaint, Middleton said he paid Paul for sex and watched her snort an unidentified drug in his living room. The next morning, he found Paul had died, Middleton told investigators.
Middleton admitted he hid the body and built a fire pit. He sent his fiancee out to buy materials to make s'mores over the fire. While she was away, he moved the body, covered it with wood and kerosene, and set it on fire.