Police are searching for a man who shot and critically injured a 45-year-old man Sunday night in South Philadelphia in front of the victim's 5-year-old son.

The gunman apparently ambushed the victim in the parking lot of a Walgreens store on the 2300 block of Oregon Avenue, police said, as the boy sat in a parked car. The assailant followed the man into the lot, got out of his car, fired 17 shots, and drove off. The child was not hurt.

The victim, whose name has not been released, was shot in the head and an arm. He is in critical condition at the Hospital at the University of Pennsylvania. Police did not comment on a motive, but said it appeared that the victim was the target of the attack.

Surveillance footage released Monday shows the victim's car pulling into the parking lot around 8:15 Sunday, and the victim getting out and standing by the car. A few seconds later, a dark gray car pulls up, and a man gets out on the driver's side and points a gun at the victim.

The shooter can be seen repeatedly firing the handgun, taking a few steps toward the victim, then backing away before getting back into his own car and driving out of the lot.

Seconds after the shooting, people in the area start approaching the victim's car, and the child is seen running from the car toward a woman who reaches to him.

Police described the shooter as a black male, between 5 feet, 10 inches and 6 feet, 2 inches, weighing 220 pounds. He was wearing a black jacket, gray hooded sweatshirt, and dark jeans. He may have been driving a Ford Taurus or Fusion that has a partial tag of FSH-456, and police say they believe a second man was in the car with him.

Anyone with information is asked to call police at 215-686-8477.