But on January 14, 2017 - just six days before Gargasoulas drove down Bourke Street killing six people and injuring dozens more - the officer was shocked the offender was released, and his warnings were ignored.

Senior Detective Gentner told the inquest that he didn’t know he could appeal the bail justice’s decision or delay the out-of-sessions hearing.

"I went in there and advised the bail justice that I'd concluded the interview with the offender during which he’s admitted a series of crimes to me," he said.

"I recall saying to the bail justice [Gargasoulas] needs to be given ... mental health and drug treatment and he won't get it if he’s left to his own devices.

"I recall saying he was an unacceptable risk of reoffending."

Days later, Senior Detective Gentner was tailing Gargasoulas on January 20 as he traversed the city in a stolen car, repeatedly trying to convince him to surrender through phone calls and text messages. He was just metres behind Gargasoulas, sending the would-be killer text messages begging him to stop, as he turned up Bourke Street.

"Don’t do this," the police officer pleaded. "Stop please. Stop for me."

At the inquest on Tuesday, Senior Detective Gentner rebuffed suggestions from the bail justice that he didn’t inform the January 14 hearing of Gargasoulas' pending charges or that the bail hearing was rushed and ill-prepared.

Gargasoulas was subsequently released on bail with conditions to report to police, not to use drugs and not to use a vehicle.

"When it was apparent he was getting bail I demanded he at least get conditions that might stabilise him and keep him in much more of a controlled state as possible," the detective said.

He said Gargasoulas was paranoid, deluded and trying hard to impress him. Gargasoulas told the bail justice he had an "understanding" with police.

"He thought he could come and work for me, he wanted to be an informer. He was basically saying he could help me solve a murder. He was deluded," Senior Detective Gentner said.

In a statement given to the inquest, the detective said he was concerned the bail justice had granted Gargasoulas bail because both were of Greek origin. He said officers were surprised in 2016 when the same bail justice released another accused offender, who was also of Greek origin.

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"I raised my concern with my bosses in relation to the bail justice, and believed that at the very least, the Department of Justice should at least covertly audit the conduct of the bail justice, particularly if the accused was of Greek origin."

'Very difficult' to shoot moving car

The inquest also heard details about the difficulties police faced at that time in stopping rogue drivers and of a string of changes to the police pursuit policy following inquiries into the deaths of drivers being pursued by police.

Senior Detective Gentner said it would be "pure luck" to stop a vehicle with a gun and that the "Hollywood film image" of police shooting out tyres would only put bystanders at risk.

"We were educated as to the fact that that wasn't a very effective way of neutralising a car," he said.

"For multiple reasons. To stop a two-tonne piece of steel [with a] bullet [would be] pure luck.

"Generally there is a method that you'll run the vehicle until it potentially runs out of fuel or to throw stop sticks in front of the vehicle to burst the tyres.

"Other than that it is very difficult to stop a vehicle."

Three-month-old Zachary Matthew-Bryant, Matthew Si, 33, Tahlia Hakin, 10, Jess Mudie, 23, Bhavita Patel, 33, and Yosuke Kanno, 25, were in the rampage.

Gargasoulas, who suffers paranoid schizophrenia, was jailed in February for at least 46 years for what was described by the sentencing judge as one of Australia's worst examples of mass murder.

The inquest continues.

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