FRESNO (KRON) — A man admitted to punching a 14-month-old baby boy to death in Fresno, according to police.

On Nov. 20, the mother let her 20-year-old roommate watch over the baby boy, Jose Luis Espinoza, while she went out.

Her roommate’s boyfriend, Kenneth Johnson, came over to visit. Two two apparently had a history of domestic violence.

Johnson says he snapped when the baby wouldn’t stop crying, so he punched him in the stomach. He was later arrested by police.

“Just a tragic sad situation what happened, you have to be on guard who you keep your kids and who you stay around,” a neighbor said.

An autopsy was determined that there was internal trauma to the child.CNN Newsource contributed to this report