A Porsche driver, who allegedly fled the scene after four police officers were killed in a horror crash in Melbourne and put photos on Facebook of the "graphic" crash scene, has been arrested.
The 41-year-old driver, who police say has an extensive criminal history, handed himself in to a police station this morning and was arrested. Fleeing the scene of a crash is an indictable offence.
His arrest comes as the officers killed in the crash have been named.
Leading Senior Constable Lynette Taylor, Senior Constable Kevin King, Constable Glen Humphris and Constable Josh Prestney - who was in his first week on the job - all died at the scene, Chief Commissioner Graham Ashton said today.
"Their names will forever be remembered, their service honoured, and their memories celebrated," he said in a statement to the Herald Sun.
"These officers were undertaking their everyday duties in helping to keep the community safe when they were killed."
Ashton earlier said the Porsche driver, who had been pulled over by officers before 5pm last night for speeding, had taken photos of the horrific scene before allegedly walking away from the crash site.
"We are pursuing with Facebook that there has been some images placed on Facebook that appear to have been taken by this individual at the scene, before he has left the scene," Ashton said.
"And some of those photographs were circulating last night online. So, I would ask if anyone is finding photographs online, not to further circulate them. In fact we are talking to Facebook this morning about removing those images from Facebook."
Ashton said the man's act was "disgusting" and said the photos were "quite graphic".
"To leave the scene is a very, very low act in my view," he said.
"If I wasn't wearing this uniform as Chief Commissioner I'd be using far more colourful language than this... but I need to be more dignified."
Two police officers intercepted the man's 911 Porsche, allegedly travelling at more than 140km/h, on Melbourne's Eastern Freeway last night.
Police also did an oral fluid test at the scene that returned a positive result for some type of drug, Ashton said.
Those two officers requested back-up and when all four were standing in the emergency lane of the freeway, making the decision to impound the speeding car, the tragic smash occurred.
"A large truck, a refrigerated truck, has then driven into these four police officers", Ashton said in an emotional press conference last night.
"The truck has also made considerable contact with the Porsche.
"The driver of the Porsche we don't believe was injured but has taken it upon himself to flee the scene on foot."
The truck's impact caused carnage at the scene with the highway patrol car being spun into the nature strip in the middle of the Eastern Freeway and the Porsche crushed under the semi-trailer.
Ashton said detectives had managed to collect footage from the four officers' body-worn cameras.
"We will be able to piece together 99 per cent of this... and get a very good picture of exactly what happened," he said.
A number of good Samaritans, including an off-duty paramedic and off-duty doctor, stopped at the scene and tried to render first aid but the four officers were unable to be saved.
Ashton confirmed this morning the truck driver had suffered some sort of medical episode and had "blacked out" after the crash.
"It's not believed he has suffered injury in the accident but has had some sort of medical episode at the scene and has been taken to hospital for medical treatment. We intend him to be there under police guard for some time."
A warrant was executed on the truck driver's Cranbourne home early this morning.
"What was found at those premises is still under investigation," Ashton said.
Ashton said this morning they have yet to interview the driver.
But what is known already is that the vehicle "appears to have moved from one of the traffic lanes of the freeway into the emergency lane and travelled a short distance in the emergency lane at around 100km/h".
The truck slammed into the back of one of the two police vehicles and collected the other police vehicle and the Porsche before coming to a stop.
Tributes for killed officers
The death of the four officers is the single deadliest day for Victoria Police in history.
One of the four officers killed has been identified as 28-year-old Constable Josh Prestney who had just started his new road policing role.
Prestney's grandmother, Eliza Anderson, told the Herald Sun he was "just on a stint before being at Kew station" and had only started on Tuesday.
Anderson has shared images on social media of her standing next to the 28-year-old, describing herself as a "proud Nan".
"You were so proud to serve, and we were so proud of you," she wrote on Facebook.
Others have paid tribute to the young officer.
"Rest in peace mate," one friend said on Instagram.
Another man wrote: "Everyone deserves to come home after work. RIP to a dear friend. You were taken from us way too soon."
According to his social media profiles, Prestney was a passionate triathlete, following in the footsteps of his parents, and a talented musician.
Senior Constable Lynette Taylor was with the Road Policing Drug and Alcohol Section where Constable Glen Humphris, through the Probationary Constable Extended Training Scheme at Collingwood, was doing a placement, Victoria Police said in a statement this afternoon.
Senior Constable Kevin King was stationed at Nunawading Highway Patrol where Prestney was doing his placement.
Ashton said all four were out of their vehicles when they were struck.
"They were dealing with this person, dealing with the impound situation and have obviously had next to no warning that the truck has arrived from where it did," he said.
Premier Daniel Andrews issued a message of support to the families of the four officers late last night.
"Tonight, four police officers lost their lives in the line of duty. And tonight, somewhere in our city, four families' hearts are breaking," he said.
"Our hearts are breaking with them. But one thing is already clear: Though we may not yet know their names – we will always call them heroes," he said.
Prime Minister Scott Morrison said Australia is "deeply grateful" to the officers "for your service".
"It is a dreadful and terrible reminder of the dangers that you face every single day. You step up every day, you stand between us and that danger every single day."