LATEST: The four police officers killed in a tragic crash on Melbourne’s Eastern Freeway have been identified.

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PREVIOUSLY: The driver of an allegedly speeding Porsche who fled the scene of a fatal crash on a Melbourne freeway has been arrested at a chemist.

The officers had pulled over a 41-year-old Porsche driver who was allegedly caught travelling at about 140kph on the Eastern Freeway in Kew on Wednesday afternoon.

He underwent a drug test which allegedly returned a positive result.

As police were impounding his vehicle, a truck, which was travelling at 100kph, came off the main lanes of the freeway and crashed into the group of four police officers who were standing in the emergency lane.

Police say the driver then fled the scene.

‘Graphic images’

The 41-year-old was arrested on Thursday morning after allegedly sharing graphic photos of the scene to his Facebook page.

“As chief commissioner, to have four officers killed last night, from someone who has clearly been driving erratically on the freeway with an extensive criminal history – it disgusts me… and to leave the scene is a very low act,” Victoria Police commissioner Ashton said.

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Ashton has asked the public not to further circulate the images.

Victoria Police is also speaking to Facebook to have the images removed, Ashton said.

Alleged history

Police say the Porsche driver had been previously known to them, with video emerging of the vehicle allegedly speeding down the same freeway just a month before it was involved in the fatal crash.

Motorist James Tsagros said he saw the same Porsche “fly past” in a 100kmh section of Melbourne’s Eastern Freeway on March 21 and captured the moment on his dashcam.

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Play Video Porche involved in Melbourne Police crash tragedy filmed speeding a month earlier Porche involved in Melbourne Police crash tragedy filmed speeding a month earlier

“This guy flew past,’’ Tsagros told the Herald Sun.

“It was just a flash.

“I have never in the 30-something years I have been driving experienced anyone drive past me doing that speed. It was actually scary.”

Officer identified

Victoria Police have identified the first of four officers killed in the crash as a new recruit who had recently graduated from the police academy.

Josh Prestney, 28, has been remembered as a “proud” member of the service.

Josh Prestney was killed alongside three colleagues. Credit: 7NEWS

Tributes have poured in, with premier Daniel Andrews echoing the heartache felt by the nation.

“To live a life in the service of others is a deeply impressive thing. To lose your life in the service and protection of others is a tragedy,” Andrews said.