James Devinn Thomas, 26, pleaded guilty Friday in Anchorage Superior Court to second-degree murder for killing fellow Air Force Airman Clinton Reeves in April 2012.

He also entered guilty pleas to two tampering-with-evidence charges.

Assistant attorney general Robert Henderson said after the hearing that the State Medical Examiner office determined Reeves died from multiple blunt force strikes to the head.

The parties agreed that the judge would impose a total sentence of 55 years with 23 suspended. That means Thomas will serve 32 years, including time already incarcerated.

Henderson said the agreement with the court is an exception to a state Department of Law policy that bars plea bargains involving sentences for the most serious classes of felony cases.

The policy change came in the wake of a state review that showed prosecutors botched a 2009 plea deal involving accused killer Jerry Active, whose trial started Thursday.

Henderson said his office crafted Thomas' sentence with the policy change in mind.

Wearing a yellow Lemon Creek Correctional Center prison suit, Thomas responded to Judge Philip Volland's questions with "Yes, sir."

Thomas was charged with Reeves' murder in June 2012. Reeves' body was discovered about a month earlier in Eagle River after he'd been missing for 20 days. Prosecutors say Thomas murdered Reeves on April 19, 2012.

Before the grand jury murder indictment, police described Thomas as a person of interest. Earlier evidence tampering charges included claims that he lied about his final moments with Reeves, burned bloody clothes in a fireplace and moved Reeves' car and loveseat, which had blood on it.

Senior Airman Reeves, 24, had gotten a $4,000 insurance company check for a wreck that totaled his vehicle, his parents told the Anchorage Daily News in 2012. He was shopping for a new car the weekend he went missing, they said.

Reeves' mother, Judy Davis, listened over of the phone as her son's killer admitted guilt. Thomas has agreed to pay an underdetermined amount of restitution to Davis.

Sentencing is set for July 24.