Two brothers who bashed a high-ranking Victorian police officer may face up to 15 years behind bars, after their bid to keep their case in a lower court failed.

Jay Stephens, 20, and Isaiah Stephens, 19, have admitted to recklessly causing serious injury to Assistant Commissioner Chris O’Neill on the grounds of St Kevin’s College at Toorak on June 15.

More serious charges of intentionally causing serious injury were dropped by prosecutors as part of the plea deal.

In Melbourne Magistrates Court on Wednesday, the duo’s lawyers applied for summary jurisdiction, which would mean their case would remain in the Magistrates Court, where the maximum penalty is two years in jail.

In the County Court, the maximum penalty for the crime is 15 years.

Jay Stephens laughed as magistrate Peter Reardon rejected the application. The magistrate said he had “serious reservations” as to whether the lower court would be able to adequately punish the duo.

“These two young men were clearly out for trouble on this particular afternoon,” Mr Reardon said.

“Whether it was Mr O’Neill or someone else there was going to be trouble and that’s what happened.”

Mr Reardon singled out Jay Stephens, who had absconded from Queensland at the time of the bashing.

“One of the accused was on parole at that particular time for crimes of violence and he absconded in relation to it. In my view … two years imprisonment would seem inadequate,” he said.

The court earlier heard Mr O’Neill, 60, suffered broken ribs, bleeding on the brain and lungs, and still had regular pain and dizziness since the bashing.

He was off duty when he followed the duo onto the grounds of St Kevin’s College after they got off a train at nearby Heyington station.

Mr O’Neill was worried they would damage property or hurt someone before finding Jay Stephens urinating against a tree, prosecutors said.

“What are you looking at you old c***?” Jay Stephens said to the officer, before the brothers began kicking and punching him in the face, head, back and torso.

In the lead up, they were accused of being loud and abusive on a train, where one was allegedly heard saying he didn’t care if they ended up in jail.

The brothers were arrested two days after the attack. Isaiah Stephens had shaved his head in order to avoid detection and his hair was found in the bin of a Malvern East boarding house.

Jay Stephens remains in custody, while his younger brother is on bail.