When Adam Peterson goes to trial in January for the murder of Joel Marino, he won't deny that he killed Marino, Peterson's attorney said Wednesday. Instead, Assistant Public Defender Dennis Burke said, the case will revolve around whether Peterson is guilty of a charge that is less than first-degree intentional homicide, the charge to which Peterson, 20, has pleaded not guilty.

Some of the lesser charges that a jury could consider are first- or second-degree reckless homicide, which would not require proof that Peterson intended to kill Marino.

On Wednesday, Burke filed a series of proposed stipulations, the first of which admits that Peterson, a former UW-Madison student, caused Marino's death on Jan. 28. Marino, 31, was found stabbed to death in his home on West Shore Drive along Monona Bay.

Police say Peterson has confessed that he committed the crime.

First-degree intentional homicide carries a mandatory life sentence. First-degree reckless homicide carries a maximum penalty of up to 60 years of prison and extended supervision, while second-degree reckless homicide is punishable by up to 25 years of prison and extended supervision.

The document goes on to admit that DNA found on the handle of a knife in Marino's home was Peterson's. DNA extracted from a backpack and knit cap found near Marino's home was also Peterson's, the document states, and it was Peterson who hid the backpack in a recycling bin where it was found.

Peterson was also taking five medications, most or all of which are prescribed for psychiatric disorders, which were found in the kitchen counter at his home, the document states.

Burke said that by getting those issues out of the way by stipulation, his defense of Peterson can concentrate on other issues. He said, however, that whether Peterson was insane at the time he killed Marino will not be one of those issues, and Peterson will not plead not guilty by reason of mental disease or defect.

"The issue at the trial will be whether he committed first-degree intentional homicide or a different crime," Burke said. "He is the guy, he did it. The question will be what was on his mind."

The case, Burke said, will turn on the interpretation that jurors give to statements that Peterson made to his parents about the murder.

During a recorded phone call from jail in Stillwater, Minn., Peterson told his father, Melvin Peterson, that he "just stabbed him out of nowhere," referring to Marino.

"I stabbed him (and) he's like, 'Why di-', he's like 'What the hell,' " Peterson told his father.

Peterson said he didn't know Marino. He told his mother in another phone call that he thought he could rob Marino of some money.

His mother asked why he would hurt someone. "That was part of the plan," Peterson told his mother. "I ... thought it was better than hurting myself."