JUNEAU, Wis. (AP) âÄî A Wisconsin prison inmate encouraged his cellmate, a high-profile killer, to commit suicide in January and helped him follow through with the hanging, authorities said Wednesday. Joshua Walters, an inmate at the Dodge Correctional Institution, was charged with assisted suicide in the death of 20-year-old Adam C. Peterson. Peterson, a college dropout, was serving a life sentence for the 2008 stabbing death of Madison resident Joel Marino. Peterson was found hanging from a bed sheet tied to his bunk bed on the night of Jan. 10, about one month after he was transferred to Dodge. The prison is in Waupun, about 55 miles northeast of Madison, and is where inmates entering the state prison system are processed. According to the complaint, Peterson’s body was found after Walters yelled to a guard that he thought his roommate was dead. Walters, who is serving time for burglary, told detectives he had nothing to do with the death. But the complaint says Walters, 20, described his role in the suicide in great detail to another inmate. In the complaint, the inmate says Walters gave him the following account: Peterson, a native of Stillwater, Minn., did not want to commit suicide then because his family was coming for a visit, but Walters persuaded him to do so. Walters advised Peterson to write a suicide note and put it in his waist band. Walters tied the noose to the bed for Peterson and made sure it would support his weight by putting his own head inside it. Then he twisted the sheet to open a hole for Peterson. Peterson voluntarily put on the noose, and Walters put a towel around his neck to help him pass out. Peterson began twitching and kicked a chair, which Walters moved because it made too much noise. Then Walters pretended to go to sleep in his bed. About an hour later, he called for help. Dodge County Sheriff Todd Nehls said it was the first time in his 30-year career an inmate had been charged with assisted suicide. His agency investigates crime at four area prison institutions, including Dodge. “He took whatever means he felt he needed to make sure that Peterson was successful in his attempt,” Nehls said. “He made sure he was successful before he alerted authorities. I think the word is ‘premeditated.’ This is something they talked about and planned.” Warden Tim Lundquist said the suicide was carefully timed to come after guards made their nightly bed checks and during a shift change. Peterson was undergoing an assessment by prison officials to determine where he should be placed, which likely would have been in a maximum-security prison, he said. He said they decided not to give him any extra security precautions even though he had tried to hang himself months earlier at the Dane County Jail in Madison. “We felt very confident he would be best served in a general housing unit,” Lundquist said. “Do we believe we did everything correct? Yes, we do.” Walters was transferred to another prison during the investigation, Lundquist said. He is set to make his initial court appearance April 27. Guards immediately removed Walters from the cell after discovering Peterson, whom emergency responders tried unsuccessfully to resuscitate. Walters told investigators that Peterson had been his cellmate for nearly a month, was “one of the best cellies” he ever had and claimed he found him hanged when he woke to go to the bathroom. Walters was moved to a cell with the other inmate, who is identified only as “JGQ” in the complaint, after speaking with investigators. Prison staff members intercepted letters from JGQ to his family members in which he described Walters’ actions. The complaint says the inmate later told investigators Walters was “nervous and paranoid” the night Peterson died and asked, “Can you get in trouble for helping someone kill themselves?” Walters described the suicide the next day, saying he and Peterson “had it all planned out,” according to the complaint. Testing at a state crime laboratory matched Walter’s DNA to the bed sheet, the complaint said. In the suicide note, Peterson indicated he took his own life to give Marino’s family “some closure.” Marino, 31, a musician, environmentalist and employee of a medical device company, was stabbed by Peterson in his own home in the middle of the day. He died in an alley as he was apparently trying to crawl to a hospital. The random nature of the murder shocked Madison and, coupled with another daytime slaying, left residents on edge. Peterson was arrested months later. If convicted, Walters faces up to 10 years in prison and a fine of up to $10,000.