A Philadelphia father was allegedly assisted by a gang of men in fatally assaulting a suspect who stole his girlfriend's car with their young children inside.

The violent incident began when an unidentified woman, 25, was traveling with her three children and stopped outside a pizza shop on 29th and Dauphin St in Strawberry Mansion, Philadelphia at 9.50pm on Thursday.

The woman was visiting her boyfriend, 25, who worked at the pizzeria and left her Hyundai Sedan running outside.

A Philadelphia father assisted by bystanders allegedly fatally assaulted a suspect who stole his girlfriend's car with their young children inside. The incident took place outside a pizza shop on 29th and Dauphin St in Philadelphia at 9.50pm, where the father of the children worked

A 54-year-old man then got into the car and took off with three children, aged 7 months, one and five, inside the vehicle.

He was able to drive about half a block before he became caught in traffic, and the couple then caught up with him and forced him out of the car, NBC reported.

The carjacker then fled on foot, but the father caught up with him and a physical confrontation ensued.

According to The Philadelphia Enquirer, police sources identified the alleged carjacker as as Eric Hood from North Philadelphia.

Other men joined in on the fight and eventually, the suspect was punched and kicked until he was unconscious.

Philadelphia Police Chief Inspector Scott Small said police were told that 'other males in the area helped the boyfriend with this physical altercation.'

He told WPVI: 'They [parents] were able to pull this car thief out of the vehicle. He fled on foot about a half a block.

'And the boyfriend caught up to him and there was some sort of physical struggle that ensued.

The woman was visiting her boyfriend who worked at the pizzeria and left her Hyundai sedan, (pictured), running outside. A 54-year-old man then drove off with three children in the car

'Then other males from the neighborhood intervened and began punching and kicking the male who took the vehicle to the point where he was rendered unconscious.'

It is not known how many individuals were involved or if the father of the children joined in on the assault with them.

In a statement, Philadelphia Police Department said: 'The parents chased down the vehicle by foot and were able to remove the male from the vehicle.

Philadelphia Police Chief Inspector Scott Small, (pictured), said that the car thief fled on foot. The father of two of the children in the car caught up with him and was joined by other men who beat the thief up

'The male assaulted the father and fled, but was stopped by a large crowd who physically assaulted him.

'The male was transported to Temple University Hospital by Medic Unit and was pronounced dead at 10.05pm.'

Police said the investigation is active and ongoing with Homicide Division and no arrests have been made at this time.

The mother and father were taken in for questioning and were said to be cooperating with police.

Authorities said a decision will be made by the District Attorney’s Office if charges are brought against the individuals involved.

The children were placed with family members, while their parents remained in custody.

Police are currently investigating surveillance footage taken from the scene which will help with their investigation.

Cops are currently waiting for the Medical Examiner's Office to determine Hood's cause of death.