A jail inmate accused of fatally beating and stabbing his cellmate in a metro Phoenix jail earlier this year told investigators that he heard voices in his head just before the attack telling him "it's either him or me."
Reports by investigators quote inmate Andrew Ward as saying that cellmate Douglas Walker had challenged him to a fight and that he heard a voice saying, "It's a death warrant; it's either him or me."
Ward was in the Maricopa County Lower Buckeye Jail after his arrest March 12 at a north Phoenix convenience store for the death of his 12-year-old half-brother.
According to MCSO, Ward fatally beat his cellmate on April 2.
MCSO said inmates notified detention officers about 7:30 p.m. of a fight inside the cell where Walker and Ward have been housed for three weeks.
Detention officers found Walker bleeding on the cell floor, faceup. MCSO said he had been beaten, stabbed with a golf pencil and smeared with peanut butter over his head. Paramedics said a plastic bag was placed in Walker's nose and throat. He was pronounced dead in jail.
Ward was questioned and admitted to detectives that he choked Walker unconscious and beat him. Ward said he attempted to cut Walker's throat with a plastic playing card, then stabbed Walker in the eye and throat with a golf pencil. Walker then stuffed a plastic bag down Walker's throat.
Ward said he had no regrets for the attack. He has been charged with first-degree murder in Walker's death.
In March, Ward told police he "just felt like killing" after the body of Austin Tapia was found with multiple stab wounds Ward pleaded not guilty to first-degree murder March 27 in Maricopa County Superior Court.
Phoenix Police Sgt. Steve Martos said Ward called police from a convenience store near the family home in the area of 35th Avenue and Deer Valley Road about 5:30 p.m. the day of the homicide.
Police found Ward at the convenience store a short time later with blood on his hands and clothing and a knife in a pocket.
Austin's mother and two sisters, ages 14 and 19, had gone to dinner that evening and said Austin had declined to join them.
They said they passed Ward as he was headed to the home, and when they returned, they were greeted by police.
Family members said Ward had a history of violence and substance abuse, and police said Ward told them nothing happened between the two that led to the stabbing.
Prosecutors are seeking the death penalty against the Ward in the deaths of Walker and Tapia.
Prior to Ward's March arrest, he had been in jail 11 different times since 2006 with "no major disciplinary problems or notable institutional history."
Walker was in custody since Nov. 27, 2013 for armed robbery and kidnapping.
Copyright 2014 CBS 5 (KPHO Broadcasting Corporation). All rights reserved. The Associated Press contributed to this report.