On Wednesday, James M. Johnson, a prisoner at the Idaho State Correctional Center, changed his plea on the charge of first-degree murder from not-guilty to guilty. In December of 2023, Johnson allegedly beat his cellmate, then 45-year-old Milo Warnock, to death. Warnock was in prison after being convicted of Driving Under the Influence. RELATED: Inmate accused of murdering cellmate pleads not guilty in Ada County CourtCourt documents show that Judge Nancy Baskins presided over the pre-trial conference. During the conference, Johnson changed his plea to guilty on the charges of First-Degree Murder and Evidence Destruction, Alteration or Concealment. The accused was indicted for the murder of Warnock on Aug. 27, 2024, by an Ada County grand jury. The trial, originally set for Feb. 3, is now vacated and a sentencing hearing has been scheduled for April 4. The maximum punishment for first-degree murder in Idaho is death or life in prison. The minimum sentence is 10 years.