Phoenix Police Sgt. Steve Martos says Andrew Ward called 911 from a convenience store near the north Phoenix home where Austin Tapia suffered multiple stab wounds late Wednesday.
Martos says Ward told the dispatcher he had stabbed someone, and officers found Ward with blood on his hands and clothing and a knife in a pants pocket.
Martos says detectives asked Ward why he killed the boy, and Ward said, "Honestly, I just felt like killing."
Martos says other family members had gone to dinner so Ward and the boy were the only ones home.
Ward was booked on suspicion of first-degree murder and child abuse. Martos says he doesn't know if Ward has an attorney.