The mom left the car running for the three young children inside, including a 7-month-old, 1-year-old, and a 5-year-old.

PHILADELPHIA — A man was killed after he stole a car that had three young children inside, CBS affiliate KYW reports.

The carjacking happened Thursday night outside a north Philadelphia pizza shop after the 25-year-old mom went inside where her 25-year-old boyfriend worked.

The mom left the engine running for the young children inside the car, including a 7-month-old, 1-year-old, and a 5-year-old. After the mom walked inside, police say a 54-year-old man hopped in the vehicle and drove off with it.

He got stuck in traffic, which allowed the couple to catch up to him. The suspect was pulled out of the vehicle and ran away.

The boyfriend reportedly caught up with the suspect, and he and other men from the neighborhood started to punch and kick him.

Medics found the suspected carjacker unconscious with severe injuries to both his head and face, WNBC reports. He was taken to a nearby hospital where he was pronounced dead at 10:05 p.m.

The parents are cooperating with investigators and have been taken into custody for questioning. The District Attorney's Office is working to decide if the father will be charged and the three children are currently staying with family members.

KYW reports police are still searching for the other men involved in the assault, which was reportedly captured on surveillance video.