Mario Alberto Lizalde Reyes turned himself into Chihuahua, Mexico police the day after he allegedly shot his best friend Mario Hernandez Banda dead, cut off his penis, and fed the severed organ to his dog.

According to Central European News, Reyes, 25, told police in his taped confession that the two were walking his dog together, both drunk, when Banda, 24, apparently tried touching Reyes "in a sexual way."

"After pushing him off, he went to urinate in an alley so I followed him, pulled out my gun and shot him in the head," Reyes told police. "I then took his knife off him and chopped off his penis as punishment and put it in a bag. But my dog was next to me and was sniffing at it so I decided to give it to him and he ate it."

Reyes then apparently left Banda's bloodied body in the alley and finished walking his dog before returning home to sleep off the alcohol. He was apparently racked with so much guilt, he turned himself into police the next day.

"He came in covered in cuts and bruises and said he had fought with his stepfather when he told him what he had done," a police spokesman told the Daily Mail. "He then admitting killing his best friend and said that although his friend had tried sexually assaulting him, he was still a human being and didn't deserve to die."

CEN reports Reyes now faces life in prison.

[Image of Reyes via CEN]