The owner of a Harbor City hamburger restaurant was shot to death Wednesday by a gunman who also fatally wounded the target of his anger, a man ordering food, police and witnesses said.

Police described the customer, a man in his 20s, as the first victim of the 9:30 a.m. shooting at Bob’s Hamburgers, a restaurant in a strip mall at Pacific Coast Highway and Normandie Avenue, across the street from Kaiser Permanente Medical Center.

• UPDATE: Suspect in custody, victims named in fatal Bob’s Hamburgers shooting

According to Los Angeles police, a man wearing a bandana over his face approached the victim in line as he waited to order food and shot him. A bullet also hit a man in his 50s who was working behind the counter.

Los Angeles police Detective Matt Maffei said investigators believe the shooting followed an earlier argument between the gunman and first shooting victim.

“We’re trying to find whoever did this,” Maffei said.

The second victim, however, had nothing to do with the altercation. He was simply working behind the counter when the gunman entered and was described by police as an “unintended” victim.

KTLA-TV identified the victim as restaurant owner Bobby Antonelos. Antonelos was taken to County Harbor-UCLA Medical Center, where he died.

Records showed Antonelos lived in San Pedro with his wife.

Antonelos reportedly was planning to retire, KTLA said.

The name of the fatally wounded customer was not released.