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 changed 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.