She left the vehicle running with her 7-month-old and 1 and 5-year-olds still on the inside while she went to see their father, who works at the restaurant.
Police say that they are continuing to investigate and are trying to track down the other males involved in the assault, reported CBS, which was captured by a nearby surveillance camera. "And the boyfriend caught up to him and there was some sort of physical struggle that ensued", Philadelphia Police Chief Inspector Scott Small told local reporters, referring to the father of the children as the woman's boyfriend. Once at the vehicle, he grabbed the auto thief and pulled him out, hitting him repeatedly.
The woman was visiting her boyfriend who worked at the pizzeria and left her Hyundai sedan, (pictured), running outside. "Then other males from the neighborhood intervened and began punching and kicking the male who took the vehicle".
The would-be auto thief then drove several blocks while the father, also unidentified, gave chase and pulled the man out of the vehicle when the auto got stuck in traffic, according to a local NBC affiliate.
The thief assaulted the father and fled, but a large crowd stopped the suspect and beat him, police said.
"I'm not a fan of street justice", said Philadelphia Police Capt. Jason Smith at the press conference Friday.
The children's parents were both taken into custody for questioning and were said to be co-operating with investigators. No arrests have been made, he said.
The city's medical examiner's office is yet to determine how the suspected carjacker died.