A 4-year-old boy accidentally shot and killed himself with his father's gun in north Houston early Sunday morning.

Jaiden Pratt was spending the weekend with his father, 21-year-old Marquiez Pratt, in the 13500 block of Northborough, just south of West Rankin, when the accident occurred, said Sgt. Brian Harris with the Houston Police Department's homicide department.

Father and son had been sleeping on the couch. The young boy woke up and picked up his father's handgun lying nearby, shooting himself in the stomach, police said. Neighbors heard the shot.

About 8:15 a.m., Houston Police Department patrol officers and an ambulance responded to the call.

The father, wearing just a T-shirt and boxer shorts, ran out of his second-story apartment, holding his son's body, screaming and yelling at neighbors for help. Upon arrival, EMTs took Jaiden from his father's arms and tried to revive the boy. He was declared dead at the scene.

"This is not a case of a responsible homeowner having a weapon for protection," Harris said. The serial number on the fired handgun listed it as stolen. It's not yet clear how the father came to possess it, Harris said.

The weapon was a .40-caliber semi-automatic pistol, which was stolen in a 2011 burglary. Several other weapons and drugs were found in the apartment, but Harris declined to provide any specifics. Harris said the living conditions at the apartment appeared to be adequate and the boy healthy.

"His mother was scheduled to pick him up at noon," Harris said, describing her relationship with the boy's father as amiable. She dropped off Jaiden with his father every Friday.

Drugs discovered

Jaiden typically called his mother at 6 a.m. when staying with his father, Harris said, and when the boy didn't call Sunday morning his mother began trying to reach other relatives.

"At about 8 in the morning, as all this was happening, she was told to get over to the apartment complex," Harris said.

Pratt faces charges of endangering a child and possession of a controlled substance with intent to deliver, said Houston Police Department spokesman John Cannon. Officers found marijuana, crack cocaine, scales and other equipment used to sell drugs in the apartment.

Cannon said the District Attorney's Office may eventually charge Pratt with making a firearm accessible to a minor, but under state law such a charge cannot be filed until seven days after the child is buried.

Harris described Pratt as cooperative and remorseful during interviews with police.

"He kept saying, 'I messed up. I messed up,'?" Harris said.

Still dressed in boxers and a T-shirt stained with his son's blood, Pratt sat on the lawn outside his apartment as he spoke with detectives before being taken into custody and driven to jail.

'Despite the choices …'

"He's in mourning. He's in pain and feels a lot of self guilt," Harris said. "Despite the choices he made and the lifestyle he was leading, it doesn't take away the love a father has for a son."

As more family members arrived at the apartment Sunday morning, a yelling match broke out that officers had to break up. One woman, trying to cross the crime-scene tape yelled, "I'm gonna kill him! I'm gonna kill him!"

Police were initially told the child was an infant.