A mum, a dad, a beloved partner, and a new recruit: The four Victorian police officers we lost this week.

The sun was only just setting on Wednesday when two police officers intercepted a Porsche on the Chandler Highway at Kew, on Melbourne’s Eastern Freeway, at 5:40pm.

The car had been speeding, and the two police stopped in the emergency lane of the freeway, calling for backup after deciding to impound the luxury car.

Shortly after two more officers arrived, the group was ploughed into from behind by a refrigerated semi-trailer.

All four died at the scene.

On Thursday afternoon, we learned their names: Leading Senior Constable Lynette Taylor, Constable Glen Humphris, Senior Constable Kevin King and Constable Josh Prestney.

WATCH: The Victorian Commissioner on the Today Show. Post continues after video.

In a statement to the Herald Sun, Victorian Chief Commissioner Graham Ashton said the officers were undertaking everyday duties to keep the community safe when they were killed.

“They were members of our Road Policing Drug and Alcohol Section and Highway Patrol. They were our colleagues, our friends, our squad mates, our family.

“Each from different backgrounds, each with different life experiences, each with a common goal to keep the community safe.

“Their families will never be the same and our thoughts and prayers are with them.”

The grandmother of Constable Josh Prestney told The Herald Sun the 28-year-old had only just begun working as a police officer: “He was just on a stint before being at Kew station. He had only started on this on Tuesday.”

Wednesday night’s tragedy was the single deadliest incident in Victoria Police history.

Previously the state’s largest police casualty was the Kelly Gang’s murder of Sergeant Michael Kennedy and constables Thomas Lonigan and Michael Scanlan in 1878.

Images from the scene show a damaged police highway patrol car and an SUV alongside a huge, white truck. The crumbled Porsche can be seen under the semi trailer, next to a blue tarp.

A witness who watched it all unfold told 9NEWS it was “utter carnage”.

The driver of the Porsche, a 41-year-old with an extensive criminal history, was uninjured and fled the scene on foot, while the truck driver is under police guard in hospital after suffering a “medical episode”. It’s not clear whether the episode occurred before or after the crash.

The Porsche driver reportedly handed himself into police in Melbourne this morning and was arrested, according to The Herald Sun. His name has not yet been formally released.

Homicide detectives had to attend the horrific scene of their deceased colleagues last night, with Victorian Police Chief Commissioner Graham Ashton describing "an eerie quiet that sometimes you don't see at crime scenes".

Their deaths have shocked the force, with other colleagues forced to deliver the news to family and loved ones overnight.

"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," said Police Association Victoria Secretary Wayne Gatt.

"This isn't the 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," he said.

Speaking to the Today Show this morning, Mr Gatt added, "the police force is waking up feeling numb, the members, the men and women of Victoria Police [will be] challenged deeply by this".

Teams will be deployed to police stations to support officers who attended the scene and those personally impacted by the deaths, with Gatt pointing out that every police station in Victoria will have some link to at least one of the four officers.

"It has just floored us. When something like this happens in policing it does send shockwaves around the force. It is one big family and that family transcends borders across the county, across the country and around the world," he said.

"Tonight, somewhere in our city, four families' hearts are breaking. Our hearts are breaking with them," Premier Daniel Andrews said last night, after hearing the news.

"We grieve alongside them – just as we grieve with every member of Victoria Police and every member of our emergency services family.

"We will always call them heroes."

Statement from the Premier:https://t.co/SlbuW5RE6I

— Dan Andrews (@DanielAndrewsMP) April 22, 2020

Flags will fly at half mast at parliament today, with the Prime Minister tweeting, "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".

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. https://t.co/alHJZO52wU

— Scott Morrison (@ScottMorrisonMP) April 22, 2020

The four officers and their stories.

On Thursday evening, Victoria Police released obituaries for the four officers killed in the crash.

Leading Senior Constable Lynette Taylor was a highly experienced and decorated member of the force.

She was also a wife to Stuart Schultz, mother to their two sons, Nathan and Alexander, and the primary carer for her sister who had recently suffered a stroke.

Lynette and Stuart were building their dream retirement home on Victoria’s south-east coast, where they planned to embrace their love of fishing and travel.

Lynette is remembered for her great sense of humour, love of adventure and her caring nature.

Constable Glen Humphris, born and raised in Gosford on the NSW Central Coast, is described by his colleagues as an officer who “genuinely wanted to help people, had a great sense of community and genuine empathy for everyone – victim and offender alike.

“Glen is remembered as being very level-headed, caring and supportive with a great sense of humour and had the ability to make light of any situation to calm people.”

He is survived by his partner, Todd.

Senior Constable Kevin King, 50, was the husband of Sharron Mackenzie, and father to William, James and Henry.

He is described as well-liked and well-respected member of the force. As one colleague put it, “He was a terrific bloke. A lovely, all round good bloke who took to road policing immediately. He would do anything in his power to not let you down. He always just wanted to laugh, have a good time, and talk about footy. It’s just devastating to lose a bloke like that.”

Constable Joshua Prestney was just 28. Though only new to the job, Victoria Police said he was a much-loved and respected member of his squad.

He is survived by his parents, Andrew and Belinda, and his brother, First Constable Alex Prestney, who presented Joshua with his badge when he graduated in December last year.

- With AAP.

Feature image: AAP