This is the shocking moment a 17-year-old girl appears to aim a replica handgun at a police officer just seconds before he shot her dead on a California highway.

Newly released police bodycam footage shows Hannah Williams with her arms raised, holding the firearm, which was later discovered to be a fake, on the 91 Freeway in Anaheim.

Fullerton Police released the distressing clip, as well as stills from the scene and the 911 call made by Hannah's father Benson to report her missing, 'in an effort to be transparent with the community that we serve'.

Police Corporal Scott Flynn saw Williams, who was driving a rental car, speeding on the freeway and attempted to pull her over on July 5 while taking his police dog to a veterinarian hospital, authorities say.

Newly released police bodycam footage looks to show Hannah Williams with her arms raised, holding the firearm, which was later discovered to be a fake

Fullerton Police say they released the distressing 15-minute clip, in an effort to be transparent with the community that we serve'

Tragic Hannah appears to aim a replica handgun at a police officer just seconds before he shot her dead on a California highway. He worried father later reported her missing to 911

Spokesman Jon Radus said: 'The gray SUV appeared to have intentionally collided with his police car.

'The driver then made an abrupt U-turn into oncoming traffic and came to a skidding stop, facing the wrong way on the freeway.'

The graphic 15-minute footage begins with Williams' SUV facing backwards on the Anaheim highway, around a mile from her home.

As the officer approaches the vehicle, walking towards the driver's side, he has his gun drawn.

When Williams comes into the picture the teen appears to have both her arms raised in what looks a shooting pose.

In the harrowing clip, high school senior and lifeguard Hannah can be heard pleading for help and telling officers she cannot breathe

When told to roll over onto her stomach and put her hands behind her back Hannah complies with both police orders and she is then handcuffed

Flynn, an officer with the La Palma Police Department from 2008 before joining Fullerton police in 2014, fires his weapon in response.

She drops what is later identified as the replica handgun, the video shows.

There is no audio for the first 30 seconds of the clip but when it does start the officer can be heard shouting 'Show me your f***ing hands! Show me your hands' after she has been wounded.

Another officer then arrives on the scene and quickly begins to help his colleague administer first aid to the girl, who appears to have been hit in her chest and leg, after securing the area.

He can be heard saying: 'It's a replica, it's a replica.'

In the harrowing clip high school senior and lifeguard Hannah can be heard pleading for help and telling officers she cannot breathe.

When told to roll over onto her stomach and put her hands behind her back she complies with both police orders. She is then handcuffed.

She says: 'Please, help me. I can't breathe.'

Hannah was taken to a local hospital where she died.

There is no audio for the first 30 seconds of the clip but when it does start the officer can be heard shouting 'Show me your f***ing hands! Show me your hands' after she has been shot

Flynn, an officer with the La Palma Police Department from 2008 before joining Fullerton police in 2014, fires his weapon in response to Hannah's stance before handcuffing her

Another officer then arrives on the scene and quickly begins to help his colleague administer first aid to the girl, who appears to have been hit in her chest and leg, after securing the area

The replica handgun designed to look identical to a Beretta 92 FS handgun which was recovered from near Hannah at the scene of the officer-involved shooting

The Orange County District Attorney's Office said earlier this month a replica gun found next to the teen was 'designed to look identical to a Beretta 92 FS handgun'.

Police said of the bodycam footage: 'Please keep in mind this is an initial review, and our understanding of this incident could possibly change as additional evidence is collected, analyzed, and reviewed.

'While body worn cameras are an excellent investigative tool, they do not always show what the officers may have seen, and vice versa, the officers don't always see and experience what the body camera footage shows.'

Witness Renay Arnold told NBC LA he saw Williams outside of her car, walking to the officer despite being told to stop.

He said: 'She looked angry and she was walking towards him, the officer. She raised both arms with a 9mm gun and he had to shoot her. He shot her. Three times. Bang bang bang.'

Hannah's family lawyer, right with her loved ones, said of the officer: 'We cannot exonerate him at this point but we certainly cannot condemn him'

Shortly after the fatal shooting Hannah's father made a call to report his daughter missing, telling the 911 handler he was worried she could be a danger to herself and that she was on medication for depression.

Asked if she had spoken about hurting herself he replies: 'No ma'am. But like I said, she is on medication right now. It's just you know out of the blue, she's never done this.'

The family's attorney Lee Merritt said of the officer: 'We cannot exonerate him at this point but we certainly cannot condemn him.'

He said he hoped the release of the footage gave Hannah's family 'a bit of closure' and that her stance did force the officer to 'make a split second decision', adding: 'He came around the corner and he saw a person in a shooting stance and it's difficult to make a split-second decision in that manner.

'We still have questions, but they can sleep better tonight knowing they have some answers.'

Paying tribute to Hannah her family called her a 'beloved daughter, sister, granddaughter, niece and friend'.