This is the horrifying moment a St Louis police officer shoots a black man five times with the officer's own personal AK-47 rifle after a high-speed car chase.

Jason Stockley, now 35, was charged in May with first-degree murder for the Decmeber 2011 shooting of Anthony Lamar Smith, 24, who was initially stopped on suspicion of taking part in a drug deal.

Smith drove off, causing a car chase that ended with Stockley shooting the man five times with his own personal AK-47-style rifle, equipped with a high-capacity drum magazine, KPLR 11 reported.

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Armed: Dash footage from St Louis cop Jason Stockley's car shows him approaching Anthony Lamar Smith, 24, with his AK-47 (left); CCTV shows Smith trying to flee, hitting cop SUV (right)

Shooting: Stockley (left, now 35) carried the personal rifle against department policy. He shot Smith (right, with daughter) five times after a car chase with his department-issued handgun

Rifle: The AK-47 and its high-capacity drum magazine can be seen here (right) on the back seat of the patrol vehicle; Stockley put it there after Smith was shot

In this Dec. 20, 2011 image from a police video obtained by the St. Louis Post-Dispatch shows then-St. Louis police officer Jason Stockley reaching into a duffle bag in the back seat of the police SUV after fatally shooting Anthony Lamar Smith

The footage, which was dropped off by an unknown party at the station, is shot from two cameras inside Stockley's car: one showing the view through the windscreen, another showing the rear seat.

It begins with Stockley, who is the car's passenger, exiting the car, which is in a Church's Chicken parking lot, with his personal rifle - in contravention of department policy.

He walks over to Smith's car, which drives away fast, brushing by him, over a sidewalk corner.

CCTV footage of the event shared by the St Louis Post-Dispatch shows that Smith had hit the police SUV while trying to reverse away.

Prosecutors say Stockley fired his department-issued handgun at Smith as he drove away, but as there is no audio on this part of the footage, this cannot be confirmed.

Stockley then returns to the car. Audio on the interior cameras begins as he calls in 'Shots fired' and a high-speed chase begins.

Fled: Smith brushed by Stockley (left) before exiting over a sidewalk (right). Prosecutors say Stockley fired his handgun here before returning to his patrol SUV to begin the chase

The cops exceed 80mph on wet roads, with driver Brian Bianchi at one point missing a corner and hitting a tree full on.

Audio is unclear, but prosecutors say that during the pursuit Stockley shouted '...going to kill this mother-f****r, don't you know it.'

Toward the end of the video Smith slows and swings toward the sidewalk, at which point Stockley says 'Hit it' and the cop car slams into the back of Smith.

'Hit it': Stockley told driver Brian Bianchi to 'hit' Smith's car (second from left) as it swerved around traffic. Smith's car was disabled, allowing the officers to leave and surround it

Death: This is the moment that Stockley (right), still carrying his rifle, shoots Smith five times with his pistol. The shooting was ruled justified as Stockley said he found a revolver on Smith

Stockley and Bianchi then exit the vehicle and surround the car, with Stockley firing five times into the car with a pistol, hitting Smith with each shot.

The shooting was originally ruled justified after a .38-caliber Taurus revolver was found on Smith's body, but prosecutors claim the gun only had Stockley's DNA on it.

That allegation casts the final scene of the video - in which Stockley returns to his vehicle and appears to rummage through bags in the back before returning to Smith's vehicle - in a curious light. The video ends there.

But footage recorded on a cell phone by a witness shows the details around that moment.

Police remove Smith - who appears dead - from the car and laying him on the road; Stockley walks away to talk to other officers before returning to his police SUV.

After rummaging in the car, he then returns to Smith's vehicle before getting into the driver's seat. It's claimed that he found the revolver there.

Prone: Footage from a witness's cell phone shows Smith, prone, being dragged from the car (at feet of officer with yellow writing on jacket)

Searching: Stockley is seen rummaging through a bag on the back seat of his SUV before returning to Smith's car and getting in (Stockley is crouching next to driver-side door)

Stockley was known to have unloaded the gun, possibly explaining the DNA, and his lawyer says he was looking for a clot pack to stanch Smith's bleeding.

But Smith's fiancée told the St Louis Post-Dispatch that she believed he planted the gun on Smith.

'Anthony didn't have a gun with him that day, and if he had a gun, it wouldn't be that revolver,' she said. 'That's just not a gun that any young guy is going to carry.'

Prosecutors haven't made the same claim, but say Stockley's DNA was confirmed by lab analysis.

Although the shooting took place in December 2011, it was only on May 16 of this year that circuit attorney Jennifer Joyce charged him with first-degree murder.

The police chief at the time of the shooting, Dan Isom, said on May 18 his investigators gave Joyce's office evidence years ago.

'Planted': Smith's girlfriend said Stockley planted the revolver in the car after getting it from his SUV. Prosecutors say his was the only DNA on it. Stockley said he was getting first aid

'Police reports, forensic analysis, video and the autopsy have been available for four years, however the circuit attorney in a criminal investigation had not reviewed any of this information until three weeks ago,' he said.

'There is no new information that was not known four years ago or discovered by the current chief.'

Joyce said police only involved her in the case in 2012, and questioned why Stockley stayed on the force until he left in 2013 if Isom was concerned.

'There is a lot of evidence we have, including witness statements that were developed after (Isom) left the police department that he would have no knowledge of,' she added.

'He's just speculating as to what we're looking at.'

A federal judge has prohibited release of the videos and police reports by lawyers who obtained it as part of a civil case in which the St. Louis Board of Police Commissioners paid a $900,000 settlement for Smith's young daughter.

Stockley is currently free on a $1million bond secured by the St Louis Police Officers' Association. Bianchi was not accused of wrongdoing and is still on the force.