A specially trained officer who blocked the Bourke Street driver’s path hours before he rammed and killed pedestrians, let the killer pass because he didn’t believe he wanted to run police down.

Senior Constable Gregory Ralston from the critical response team told an inquest he was locked in a “Mexican standoff” with James Gargasoulas on the morning of January 20, 2017.

The offender, on the run from police in a stolen car after stabbing his brother, was travelling up to 40 kilometres an hour when his path was blocked by Sen Const Ralston and his partner’s vehicle in South Melbourne.

Sen Const Ralston said Gargasoulas slowed down and indicated for him to move to avoid an accident.

“I took that to mean he didn’t want to ram police or that he wasn’t trying to run us down in any way, he just wanted us out of the way,” he said.

“It happened so quick. There was a Mexican standoff, so to speak. I was thinking we either attempt to block him in or move the vehicle out of the way.

“The car was on us. That’s when I made my decision. I just turned right and allowed him to pass.”

The officer said Gargasoulas could have easily passed police by mounting the gutter but at the time he didn’t see that as an option.

A police pursuit of him ensued shortly after, but ended due to safety reasons.

On Monday, Sergeant Matthew Peck, who was in the vehicle with Sen Const Ralston, conceded the encounter was a missed opportunity to arrest Gargasoulas, who later that day drove onto city footpaths mowing down pedestrians, killing six and injuring 27 others.

The inquest continues.

-AAP