A 26-year-old man with a long history of violence was on bail when he allegedly drove the car that killed four people and injured more than 20 others in the heart of Melbourne on Friday afternoon.

Dimitrious Gargasoulas, 26, the man police allege is responsible for the deliberate car attack. has emerged as a deeply troubled person that police were largely powerless to stop.

As the city came to terms with the unfolding tragedy, police today told reporters that they had opposed bail during his January 14 out-of-sessions hearing.

Chief Commissioner Graham Ashton said police sometimes expressed frustration that some accused were released against police recommendations.

“The courts are independent. I wouldn’t be doing my job if I didn’t reflect that police were often frustrated in relation to trying to keep people in custody and they’re bailed.”

On Friday afternoon, he allegedly ploughed a stolen Holden Commodore into pedestrians in the CBD of the Victorian capital, killing four, including a child. At least 20 others were injured, five of them critically.

Three of the dead died at the scene while the fourth victim passed away Friday night.

A three-month-old baby girl who was rushed to hospital by police officers is one of those battling life-threatening injuries.

Yesterday’s lunchtime mayhem only stopped when Gargasoulas was shot in the arm by police. He was under police guard last night in Melbourne’s St Vincent’s Hospital.

The only suspect was described by police as having a history of violence, drug use and psychological problems.

Gargasoulas had been wanted over the stabbing of his brother, Angelo, at their ­mother’s Windsor home at 2.15am Friday.

Over the next 11 hours he was seen at various locations in Melbourne’s south, west and city.

At one point, in the western suburb of Yarraville, Gargasoulas allegedly shouted: “Armageddon is coming. The end of the world’s going to come today. Watch the news.”

Then, around 1.30 pm Friday, he turned up at one of Melbourne’s busiest intersections and stunned city workers and visitors by doing “doughnuts” in the stolen car at the corner of Flinders and Swanston Streets.

He then drove four blocks north on Swanston Street, which is supposed to be a tram-only zone, before turning west into Bourke Street where the worst of the horror unfolded.

Gargasoulas’ Facebook page is full of machismo. Photo: Facebook

Victoria Police chief commissioner Graham Ashton said Gargasoulas had “an extensive family violence history” and had “come to our attention on many occasions”.

“We also have mental health and drug-related issues in the background of this particular person. He has been coming to our attention more recently over recent days in relation to assaults, family violence-related assaults. He was also charged by us over the course of last week.”

Gargasoulas was reportedly bailed by a bail justice on the weekend on charges of theft and assaulting his mother’s partner, Gavin Wilson.

Mr Wilson, 74, who lives in a public housing flat in Windsor, told The Age that Mr Gargasoulas was ”a nice kid”, but said on Wednesday night he became violent, setting fire to a Bible and throwing it at his face and punching him.

Gargasoulas’ public Facebook page shows repeated posts about the movie Scarface, as well as him posing in front of a military tank.

The maroon car the suspect allegedly used to mow down pedestrians reportedly belonged to Mr Wilson.

Chief Commissioner Ashton confirmed that police cars and a helicopter had been following the vehicle as it entered Melbourne’s central streets, but that they deemed his driving to be “too dangerous” for them to intercept.

“We then brought in the support of the air wing, who were maintaining obs [observation] as we tried to find another opportunity to intercept the vehicle.”

Several sources have told The New Daily that an internal debate is raging within Victoria Police about a recent policy change that makes it harder for officers to apprehend suspects who drive at speed. The policy is intended to protect officers, the public and suspected criminals from harm.

Some of Melbourne’s most central streets were locked down for several hours. Photo: The New Daily

Senator Derryn Hinch wrote on Twitter on Friday night: “I’m told pursuing police had 7 chances to ram the Bourke Street killer and were denied permission.”

Earlier, he wrote: “If this man was on bail all hell will, and should, break loose.”

It is understood police began pursuing the car on Friday morning. Commissioner Ashton said there was a woman in the vehicle as it travelled over the Bolte Bridge towards the city from Yarraville. She exited on the bridge.

He said investigators were trying to determine why she was in the car, or if she was being held hostage.

Police stressed the incident did not appear to be linked to terrorism or organised crime.