A Philadelphia police officer has been charged with murder after footage showed him fatally shooting a 27-year-old motorist in his car last month.

Eddie Irizarry was killed while sitting in the driver’s seat of his vehicle holding a knife, say prosecutors.

Body camera video of the incident shows two officers pulling over Mr Irizarry for a driving infraction, before one of them fires multiple shots at him.

The officer, Mark Dial, 27, turned himself in to police on Friday morning.

Two days after the 14 August shooting, police walked back their initial statement on the shooting. They originally said Mr Irizarry had lunged at police from outside his vehicle while holding a knife.

But body camera footage released by Philadelphia prosecutors on Friday clearly shows Mr Irizarry was sitting in the driver’s seat of the vehicle when the officer opened fire.

Police said investigators are working to determine how the false account of the incident emerged.

On Friday, a lawyer for Mr Dial said his client had opened fire because he thought he saw Mr Irizarry holding a gun.

“Fearing that he was going to be the next police officer killed in the streets of Philadelphia, he fired,” attorney Brian McMonagle said.

He added that Mr Dial intends to fight the murder charge.

Mr Irizarry had parked his Toyota Corolla on a road in Kensington, a neighbourhood of Philadelphia, after police said he was pulled over for turning on the street in the wrong direction. It was midday.

Mr Dial and his partner pulled up next to him in a police vehicle.

Prosecutors said that at one point, Mr Irizarry is seen holding “a small, open folding knife against his thigh”, and that his window was rolled up.

Mr Dial is heard in the police body camera footage shouting “show your hands” at Mr Irizarry before threatening to shoot him.

Around five seconds later, the officer fires multiple shots at Mr Irizarry, who was still sitting in the driver’s seat.

After the shots were fired, Mr Dial’s partner is heard saying: “Mark, hold on. Mark, stop.”

The video shows the two officers pulling an unresponsive Mr Irizarry out of his car and into the backseat of a marked police vehicle. They drive him to hospital.

Philadelphia District Attorney Larry Krasner said on Friday the family of Mr Irizarry had seen the video last week, and wished it to be made public.

“What they said to us was that they wanted the videos played in their entirety, they wanted no portion of these videos blurred,” he said.

Mr Irizarry’s aunt, Zoraida Garcia, told reporters at a protest last week that the clip was difficult to watch.

“Seeing my nephew just sitting in the car not doing anything,” Ms Garcia said. “And it’s horrible.”

Mr Irizarry’s family said that he had come to the US from Puerto Rico seven years ago, and that he was working as a mechanic. He was reportedly being treated for schizophrenia.

The family has said that they intend to sue both the city of Philadelphia and the officer for wrongful death.

Mr Dial, who has been an officer for five years, was suspended for 30 days after the incident, accused of insubordination.

According to Philadelphia Police Commissioner Danielle Outlaw, the officer refused to co-operate with an investigation into the shooting.

Mr Irizarry’s death has angered many in the Philadelphia community, who have rallied behind his family and held protests to demand answers from the police.

After the footage was released, Mayor Jim Kenney said in a statement: “We ask that the public remain peaceful in demonstrations and calls for accountability as we continue to process this tragedy as a city.”

Police Commissioner Outlaw said in a statement the internal investigation will be done in a “fair, equitable and transparent manner”.

The union representing Philadelphia police officers spoke out in support of Mr Dial.

They asked people “to reserve judgment until all the evidence is presented during trial”.

Mr Dial was arraigned on Friday afternoon and released on bail, which was set at $500,000 (£400,000).

He is due to appear in court for a preliminary hearing on 26 September.