A 27-year-old man from West Virginia faces murder charges after confessing to having thrown his 1-year-old stepson on Sunday because the child was fussy and refused to nap.

The boy suffered a skull fracture and died at a hospital about an hour after emergency crews were called, WDTV reported.

Zachary Williams, 27 was charged with first degree murder.

According to the police, the grandparents of the baby, who lived with Williams and the child’s mother, reported that the boy had been well in the morning apart from having a cold.

Investigators learned that the boy had bumped his head while crawling, which resulted in a “little red mark.” There was a bruise above his left eye, but an autopsy revealed a severe skull fracture at the back of his head.

The baby’s mother told the medical examiner that the child had been fussy because of his cold, and that she fed him breakfast Sunday morning before the grandparents left the house. Then she decided to put him down for a nap.

When the boy fought sleep more than usual, she woke up Williams for some help, the criminal complain says. He took the baby into the bedroom and soon began calling for the mother, who found her son limp. She called 911 and started CPR.

Williams told police he was bouncing the boy to try to soothe him, but that he suddenly went “rigid and limp” and became unresponsive.

After the autopsy, Williams admitted that he threw the baby out of frustration, slamming his head on the bed frame and the floor. He told investigators at that point that “it was all his fault.”

Williams was ordered held without bond.