LATEST: The truck driver involved in a crash which claimed the lives of four Victoria Police officers has been identified.

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PREVIOUSLY: One of the four police officers killed in a tragic crash in Melbourne has been identified as a new recruit who had recently graduated from the police academy.

Josh Prestney, 28, died alongside three colleagues on Wednesday afternoon when a truck crashed into them as they were standing in the emergency lane of the Eastern Freeway in Kew.

“You were so proud to serve, and we were so proud of you,” Prestney’s grandmother said in tribute to him.

“He only graduated in November. He was just on a stint before being at Kew station. He had only started on this on Tuesday,” she told the Herald Sun.

Josh Prestney, 28, died alongside three colleagues on Wednesday afternoon. Credit: Supplied

The four officers were standing in the freeway’s emergency lane to impound a Porsche that had allegedly been seen travelling at about 140kph.

The vehicle’s driver allegedly returned a positive drug test result.

In the video below: Four Victoria police officers killed while on duty

Play Video Four Victorian police officers have been killed while on duty Four Victorian police officers have been killed while on duty

As the officers were standing in the lane, the truck, which had been travelling at about 100kph, crashed into them.

Despite the efforts of good Samaritans, the officers died at the scene.

Tributes in

Victoria Police Chief Commissioner Graham Ashton said the officers “sacrificed their lives” on the job.

“It is a tragic day for Victoria police,” Ashton said.

Emergency services at the scene of the crash on Thursday. Credit: Scott Barbour / AAP

“A tragic day for the families of these officers and we feel very deeply for them.

“The whole force is reeling this morning from what’s occurred last night.

“It’s an unprecedented event for us to lose so many officers in one event, in one terrible collision on the freeway.

The four officers died at the scene. Credit: Scott Barbour / AAP

“And officers just doing their work, doing the job, doing a duty that is performed by officers many times a day across a state.

“It is just a timely reminder of how tragic these police work can be at times.”

Police believe the truck driver suffered a medical episode immediately after the crash.

‘Terrible tragedy’

A minute’s silence was held at the Victoria Police Academy on Thursday morning to pay their respects to their fallen colleagues.

A scaled-back Victorian Parliament also started Thursday’s proceedings with a minute’s silence for the officers.

Earlier, Premier Daniel Andrews has told reporters at a press conference the crash was a “terrible tragedy”.

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“To live a life in the service of others is a deeply impressive thing,” he said.

“To lose your life in the service and protection of others is a tragedy.”

Investigations into the crash continue.