Robert Anthony Cannon, 20, was among four men convicted of breaking into a house wielding baseball bats early on August 6, 2004.
Cannon pleaded guilty to first-degree murder last year after prosecutors agreed not to seek the death penalty.
He later refused to testify at the trial of his co-defendants and said he wanted to withdraw his plea, but a judge rejected that request.
Three other men were convicted of first-degree murder last month: Troy Victorino, 29, Jerone Hunter, 20, and Michael Salas, 20. Salas was sentenced on August 1 to seven life terms.
Victorino and Hunter are awaiting formal sentencing after a jury recommended death for both men.
Victorino was accused of organising the attack because a girl who lived at the house had an Xbox video game system and other belongings from a house he was squatting in.