Victoria Police Chief Commissioner Graham Ashton has revealed one of the four police officers killed in the Eastern Freeway tragedy was still in training.

The police officer, a man aged in his 20s, was on placement as part of his studies at the Victoria Police Academy.

“They go and do a few weeks out on a placement in the workplace, so they learn on the job. He was doing that,” Mr Ashton revealed to 3AW’s Neil Mitchell.

The Chief Commissioner said another officer who was killed had only recently finished training, while a third, a woman in her 60s, was a long-term member who had spent “many, many years in the job”.

“It’s definitely a dark day for us, and one that’s going to take a long time for us to work through,” he said.

While social distancing will make honouring the slain police in the usual way difficult, Mr Ashton said they will be remembered.

“We’re going to have to do something and stream it and then when we can, when it’s lawful to do so, we’ll have a large commemorative service,” he said.

“We’ll do everything we can to make sure we acknowledge these officers for the heroes they are and make sure that the community understands the sacrifice they’ve made.”

Neil Mitchell this morning started a campaign urging Victorians to put something blue out the front of their houses to honour the fallen police, and many have already answered that call.

Press PLAY below for more.

Blue blitz: Victoria turns blue with tributes to fallen police

Image: Vince Caligiuri / Stringer