An Arizona man confessed to killing his teenage son with an ax on New Year’s Eve because he thought the boy was a demon, police said. Investigators said 51-year-old Gary Sherrill, of Phoenix, was afraid of his son, David, and believed the boy was going to eat him. The teen’s mother asked police to check on the boy Tuesday because her ex-husband had not returned him, as scheduled, and she hadn’t been able to reach either of them by phone. Sherrill initially told police the boy wasn’t home, but police persuaded him to invite them into the house. “Once inside, they located the 13-year-old male victim, David Sherrill, deceased with obvious signs of trauma,” Martos said.