Investigators say the boyfriend, who is the father of two of the children, chased the suspect on foot and was able to catch up to the auto when it got stuck in traffic. She had their 3 children in the auto with her and she left them there while she dashed in.
District Attorney Larry Krasner told local media it was too early to comment on any potential charges, but authorities are using footage from a nearby surveillance camera to search for the other men involved in the beating.
The children in the vehicle were not harmed, police said.
"They were able to pull this auto thief out of the vehicle". He only got about a half block away before dad ran him down again.
The other men who jumped in the fight were not located.
Philadelphia Police Chief Inspector Scott Small, (pictured), said that the auto thief fled on foot.
Hood assaulted the father and fled, but a large crowd stopped Hood and beat him, police said.
The man was taken to hospital with severe head and facial injuries.
The children's parents were both taken into custody for questioning and were said to be co-operating with investigators.
"I'm not a fan of street justice", Philadelphia Police Capt Jason Smith was quoted as saying by CBS. No arrests have been made, he said.
Police are now investigating surveillance footage taken from the scene which will help with their investigation.
Cops are now waiting for the Medical Examiner's Office to determine Hood's cause of death.