The shooting happened in the 11000 block of Wagner Street just before midnight Sunday, according to the Los Angeles Police Department. The boy's mother was also home at the time.
"The father was transferring his 8-year-old from his bedroom into his child's bedroom when he heard the front door open,'' LAPD Sgt. Frank Preciado said. "At that point, he assumed it was his 20-year-old son.''
Instead, the resident was confronted by the gunman, who had walked in through the unlocked door. The suspect got into an argument with the father and began pursuing him through the house, firing about 10 shots, some of which penetrated the wall of the boy's bedroom, police said.
"He was saying, 'I've got children in my room,''' Preciado said. "It was heart-wrenching. We don't know exactly what transpired between these two adults, but the children actually were innocent.''
No description was available of the suspect, other than he was a male wearing a gray hooded sweatshirt, according to Capt. Nicole Alberca of the LAPD's Pacific Division. She said family members did not know the suspect and police had no idea what the motive was.
A photo of the boy was released, but not his name. He was still hospitalized in critical but stable condition, police said.