Houston Police Department Marquiez Deshon Pratt

A 4-year-old Houston boy fatally shot himself with his father's stolen handgun Sunday morning, police say.

Marquiez Deshon Pratt, 21, was asleep on the couch when his son, Jaiden, picked up the gun and shot himself in the stomach, according to a report from the Houston Police Department.

The weapon, a .40-caliber semiautomatic pistol, was stolen during a burglary in 2011, according to the police report.

Jaiden was spending the weekend with his father when the incident occurred. The boy's mother dropped him off every Friday and was scheduled to pick him up Sunday at noon, according to the Houston Chronicle.

After the shooting, the elder Pratt ran out of his second-floor apartment with his son in his arms, yelling to his neighbors for help, according to the Houston Chronicle.

When officers arrived, Pratt handed his son over to them and ran back to his apartment.

While some officers pursued Pratt, others performed CPR on the young victim, but the boy was pronounced dead at the scene.

The officers who followed Pratt into his apartment discovered marijuana and crack cocaine along with weighing scales and other items used to sell drugs, according to the police report.

Pratt was arrested and charged with injury to a child by omission and possession of a controlled substance with intent to deliver.

"He's in mourning. He's in pain and feels a lot of self guilt," Sgt. Brian Harris, of the Houston PD's homicide department, told the Houston Chronicle. "He kept saying, 'I messed up. I messed up.'"