The father of two brothers accused of brutally attacking one of Victoria's most senior police officers has a long history of violence, a court has heard.

Key points: Police have argued Mr Pihlgren had previously been convicted for making threats to kill

Police have argued Mr Pihlgren had previously been convicted for making threats to kill His lawyer argued his last conviction for physical violence was in the 1990s

His lawyer argued his last conviction for physical violence was in the 1990s He has been released on bail but will not be able to contact his sons or use social media

Jared Pihlgren, 49, is charged with posting threatening messages on Facebook after his sons, Jay and Isaiah Stephens, were arrested for allegedly assaulting Assistant Commissioner Chris O'Neill in June.

Mr O'Neill, who oversees safety on Victorian public transport, was hospitalised with bleeding on the brain.

Senior Constable Angela LeSeur told the Melbourne Magistrates' Court today that Mr Pihlgren's most recent convictions in 2018 and 2017 were for threatening to kill people.

"In one post he said, 'When I catch you in the street I'm going to hurt you. I am going to hunt you down'," she said.

She said Mr Pihlgren was an unacceptable risk and should not be released from custody.

But his lawyer, Rory Hudson, argued that the threats were made on social media and his last conviction for physical violence was in 1998.

He added that there was an eight-month delay in having his phone and tablets forensically examined and Mr Pihlgren would be forced to spend another eight months in jail, which is more than the potential sentence for the offence he is charged with.

The magistrate released Mr Pihlgren on bail with the strict conditions that he does not use social media and does not contact his sons.

Jay Stephens, 20 and Isaiah Stephens, 18, are each facing multiple charges, including intentionally causing serious injury, for allegedly attacking Assistant Commissioner O'Neill.

The pair appeared on court in June. The court heard the men were drunk while on a train from Southern Cross station when they were ejected at Heyington Station for vomiting and anti-social behaviour.

Assistant Commissioner O'Neill was on the train platform and followed the men to the grounds of St Kevin's College in Toorak where they confronted him, the court was told.