Richard Pusey (pictured) is allegedly in police custody after fleeing the scene of the accident on Wednesday night

Victoria Police's Chief Commissioner says he is disgusted that the driver at the centre of the crash that killed four officers took gruesome photos of their bodies and posted them online before fleeing the scene on foot.

Police allege Richard Pusey was pulled over while travelling 140kph in a Porsche 911 on the Eastern Freeway in Melbourne about 5.40pm on Wednesday.

Minutes later, a truck crashed into the group of police standing at the roadside, killing four officers.

The 41-year-old, who allegedly has an 'extensive criminal history' and tested positive for drugs at the scene, handed himself in to West Melbourne police station with a solicitor on Thursday morning, Herald Sun reported.

Mr Pusey, a mortgage broker, made contact with police and was urged to turn himself in. He is currently assisting the Homicide Squad with the investigation.

Mohinder Singh Bajwa, the driver of the truck - who had a 'medical episode' - remains under police guard in hospital.

Three male officers - including one in his first week in the job - and a female senior constable who were standing in the emergency lane on the side of the freeway were killed when the out-of-control truck veered into the group.

The police car that arrived at the scene was crushed by a refrigeration truck about 5.40pm on Wednesday

Police pulled over a speeding driver at 4.50pm on Wednesday, then proceeded to call for backup from highway patrol when they decided to impound the car. By 5.40pm, the refrigeration truck had ploughed into the three cars and four officers, killing them all

Four police officers were killed when they were struck by a truck (pictured at the tragic scene) in Melbourne, marking the greatest loss of police life in a single incident in Victoria's history

Chief Commissioner Graham Ashton said the driver took photos of the dead police and posted them on Facebook.

A source told Daily Mail Australia the pictures were mostly of the wreckage, and had also been posted to Snapchat.

'As chief commissioner, to have four officers killed last night with someone who has clearly been driving erratically on the freeway with an extensive criminal history it disgusts me,' Commissioner Ashton said.

'Today, when I'm spending time with the family members of those deceased officers, I can tell you it will absolutely disgust them.'

He went on to say the driver's actions were 'very, very low', made worse by the decision to share photos of the grisly scene to friends.

'If I wasn't wearing the uniform of Chief Commissioner, I would give you far more colourful language,' he said.

'We will definitely be able to piece together 99.9 per cent of this. We have got a lot of information to go through in the next few days.'

The first victim has been identified as constable Josh Prestney, who only graduated from the academy in November (pictured)

'If I wasn't wearing the uniform of Chief Commissioner, I would give you far more colourful language,' Commissioner Ashton said

The black Porsche sped past him and was gone in a flash - as seen on dashcam footage from March 21

Emergency services took the bodies of the four police officers away from the scene

Josh Prestney, a 28-year-old constable who had only started in the road policing department on Tuesday was killed at the scene.

Mr Prestney only graduated from the academy in November, and was working a short stint in the unit before he was to be transferred to Kew police station in Melbourne's eastern suburbs.

Another officer had reportedly been part of the team for eight years - leaving behind a devastated wife and children, his cousin, Trevor, told 3AW on Thursday.

Chicken truck driver Mohinder Singh Bajwa blacked out following the accident on the Eastern Freeway near Kew, Melbourne, on Wednesday evening

'It's just devastating. They're not a number, they're a name, they're a family member, they're a friend, they're a cousin, they're an uncle and a brother, or a husband, or a wife,' he said.

Commissioner Ashton said they expected to interview Mr Bajwa, who was driving the truck, later on Thursday.

'He is from Cranbourne and we did a warrant through the night at his premises,' he said. 'What was found at that premises is still the subject of ongoing investigation.'

Mr Bajwa's university student son, Gurdeep, declined to comment on the investigation.

'I'm not able to talk to anyone, not able to share any comments,' he said. 'I'm not able to speak'.

Connect Logistics, the company which owns the truck, did not answer calls.

This morning Police and Protective Services Officer recruits, instructors and staff at the Victoria Police Academy formed up on the parade ground (for a minute's silence) to pay their respect and honour their fallen friends and colleagues

Emergency services were called to the scene to remove the truck, as well as the three crushed cars

Pictured: Moments before the truck ploughed into the officers and the Porsche, as officers speak with the driver in the emergency lane of the freeway

First victim identified as 28-year-old Josh Prestney The first victim of the horrific crash which cost four Victorian police officers their lives has been identified as 28-year-old Josh Prestney. Mr Prestney had only graduated from the academy last November, and was working a short stint with the road policing unit before he was to be transferred to Kew police station. His grandmother Eliza Anderson told the Herald Sun Mr Prestney was 'so proud to serve' his community. He had reportedly only started in his new role on Tuesday, the day before the accident. 'We were so proud of you. God bless Josh. Miss you forever,' she wrote on Facebook. Advertisement

Police believe the truck veered into the emergency lane and travelled 'some distance' before colliding with the cars - and officers - at about 100km/h.

It comes as chilling footage emerges of the Porsche speeding down the same highway a month before it was involved in the accident.

Motorist James Tsagros saw the exact same car 'flying' down the same freeway at 'scary' speeds on March 21.

When officers from the road policing drug and alcohol unit pulled the Porsche over on Wednesday night, they made the decision to impound the luxury sports car.

They called a nearby highway patrol car for backup. As the officers arrived, the refrigeration truck ploughed into all three stopped cars, killing the two senior constables and two officers as they stood in the emergency lane.

The Porsche was filmed speeding down the highway a month prior to the accident on Wednesday (pictured)

Flowers have begun piling up outsied the Boroondara Police Station in Melbourne's north-east

Police colleagues and emergency workers paid tribute to the fallen officers in what is the greatest loss of police life in a single incident in Victoria's history.

Chief Commissioner Ashton said detectives were trying to piece together what led to the crash, but labelled the tragedy a 'crime'.

When asked why homicide detectives were at the scene on Wednesday night, he replied: 'Those officers (who died) have been victims of a crime.'

The incident represented the largest loss of life for Victoria Police in a single incident, eclipsing the loss of three officers gunned down by bushranger Ned Kelly in the state's north-east in 1878.

Word quickly spread throughout the force as grieving officers changed their Facebook profile photos to one of a fallen angel in honour of their dead colleagues.

'It's absolutely f***ed… Trying to find out exactly what happened… A real horrible and shocking tragedy,' one shattered officer wrote.

'No words,' another posted alongside a photo of the Victoria Police emblem.

Many of the killed officers' colleagues changed their Twitter profiles to the same fallen angel picture.

'To my Victoria Police colleagues, first responders, investigators and most importantly the families of officers- my heart goes out to you all,' one wrote.

The truck ploughed into two parked police cars and a black Porsche, which is pictured covered in a blue tarp. The driver of the luxury sports car allegedly fled the scene

'This is an incomprehensible tragedy... I have no more words but to say look after each other & reach out to your support networks. Take care.'

A MyCause campaign has been launched to support the families of the victims.

Senior Constable Steven Pope is aiming to raise a total of $2million, or $500,000 for each family.

More than $29,300 has been raised by 442 donors in just 12 hours.

'This is a brutal reminder of the danger police face in the course of their service, every minute of every shift,' Constable Pope said.

'Whilst we mourn their loss, we grieve with their families and colleagues. Whilst money can never replace a lost loved one, the financial stresses can take their toll.'

The tragedy has rocked officers and emergency service workers throughout the nation

Emergency services were on the scene on Wednesday night to remove the wreckage from the scene on the Melbourne freeway

Victoria Police was inundated with heartfelt tributes from interstate colleagues

'There's an eerie quiet down there [at the scene], everyone down there is feeling it at the moment,' Commissioner Ashton said in a conference on Wednesday night.

'It can sometimes seem mundane and then can suddenly seem very very tragic.'

It is unlikely the four officers will receive a traditional large scale police send off - as coronavirus restrictions limit funerals to no more than 10 people to slow the spread of the virus.

'If we're still in restrictions, we won't be able to have those large scale remembrance ceremonies we traditionally have to honour our police officers,' Commissioner Ashton said.

Police Association Victoria secretary Wayne Gatt also spoke of the incident, saying it would reverberate among police stations throughout the nation.

'This will be felt in every police station, in every mess room, in every watch-house across the state tonight,' he told reporters late Wednesday.

Police confirmed one female and three male officers were killed in a horror crash in Melbourne

The crash on Melbourne's busy Eastern Freeway sparked chaos on Wednesday night

'Those members, today, when they started their shift came to work expecting to protect the community. That much they did do. That much we are proud of them for doing.

'These police officers were doing something that we do 10 times, 20 times, 30 times a shift - intercepting a motor vehicle on the side of the road, this is the bread and butter of policing,' he told reporters.

'This isn't stuff that you go to do and expect to be killed doing. But each and every time a police officer does that for the next little while, they'll have this in the back of their minds, there's no doubt.'

Witnesses described the scene as carnage.

'There were civilians trying to run around and help, it was horrible,' one told the Herald Sun.

Debris from the fatal crash was scattered along the Eastern Freeway, which remains closed

It's understood a semi trailer (pictured) ploughed into two parked police cars and a Porsche

Dan Smith was heading outbound along the freeway when he saw at flashing lights, least 12 to 14 police cars and several ambulances at the scene.

'The police members were sprinting from their cars,' he told the Age. 'I could see the truck and then I saw the crumpled mess of the Porsche.'

A half-crushed silver highway patrol car was sitting on the grass on the median strip.

All lanes of the Eastern Freeway were closed between Bulleen Road and the Chandler Highway for most of the night as officers from the homicide squad and major collision units investigated.

The Coroner also visited the scene on Wednesday night.

Photos of the scene show a damaged police highway patrol car and an SUV that had been struck near a large, white semi-trailer.

The black Porsche crumpled beneath the truck was covered in a blue tarp.

Police urge anyone who witnessed or has information in relation to the crash to contact Crime Stoppers.

All lanes of the Eastern Freeway are closed due to a fatal crash involving a truck (pictured)

Four police officers were killed in the horror crash. Pictured is the tragic scene

Politicians offer condolences to officers killed in the line of duty Political leaders have offered their condolences to the fallen officers. Prime Minister Scott Morrison 'Awful, heart-breaking news that four police officers have been killed while on duty in Melbourne tonight. My deepest sympathies go out to their families, fellow officers and friends at this terrible time,' Prime Minister Scott Morrison tweeted. Opposition leader Anthony Albanese added: 'Heartbreaking news out of Victoria. These officers were killed while doing their jobs – a terrible reminder of the risks taken by police and emergency workers every single day. My deepest condolences to their families, friends and everyone at Victoria Police.' Victorian Premier Daniel Andrews also penned a heartbreaking tribute. 'Tonight, somewhere in our city, four families' hearts are breaking. Our hearts are breaking with them,' he said. 'We grieve alongside them – just as we grieve with every member of Victoria Police and every member of our emergency services family. 'In the coming days, formal investigations will tell us why – how – this could possibly have happened. 'But one thing is already clear: Though we may not yet know their names – we will always call them heroes. Police minister Lisa Neville later announced that flags will be flown at half-mast at Victoria's Parliament House on Thursday following the 'unimaginable tragedy' 'They [the victims] are Victorian heroes tonight,' she said. 'Victoria Police have done an incredible job the past few weeks. Now is the time to really thank them. 'Just a thank you, a nod, a wave ... to send a strong message ... a positive message and thank police for the work that they do. Advertisement