Police are looking for an intruder who opened fire in the home of an 8-year-old boy, leaving the sleeping child with a gunshot wound to the head as his father tried to shield him.

Detectives also sought a motive for the attack that sprayed bullets through a wall and into the bedroom in the Del Rey neighborhood near Venice Beach.

"According to the family, they did not recognize the suspect," and there was nothing in the house that indicated drugs or other illegal activity, Los Angeles police Capt. Nicole Alberca said at a news conference Monday afternoon.

The boy had just gone to bed around 11:55 p.m. Sunday when the father heard the unlocked security door and front door open, Sgt. Frank Preciado said.

The father had been expecting his 20-year-old son, but when he walked into the living room, he saw a stranger in a gray hooded sweatshirt, Preciado said.

They exchanged words, then the intruder pulled a gun and fired about 10 shots, none of which hit the father, who was only about 5 feet away, Preciado said.

The father then ran into the boy's bedroom and tried to shield him, while the gunman was following and still firing, Preciado said.

"He was saying, `I've got children in my room,"' Preciado said.

Bullets broke through the wall and the bedroom door, although it was unclear which bullets struck the boy. The wall may have slowed the gunfire, police said.

The boy underwent surgery for a head wound and was listed in critical but stable condition, police said.

No other family members, whose names police withheld, were injured. The boy's mother and 17-year-old brother also were in the bedroom, and his grandmother was in another room, Preciado said.

Shootings are rare in the residential neighborhood, police said.