Truck driver Mohinder Singh has appeared in court charged with culpable driving over the Melbourne freeway crash that killed four police officers.

The 47-year-old Cranbourne man was charged with four counts of culpable driving over last Wednesday’s fatal collision, police said early on Monday.

Shortly after the crash on Wednesday the truck driver was taken to hospital under police guard with non-life-threatening injuries. The Victorian police commissioner, Graham Ashton, said he had had a medical episode at the scene and had been tested for the presence of drugs and alcohol as part of the inquiry.

The driver, who was in hospital until Sunday night, was charged after a joint investigation by the major collision investigation unit and the homicide squad.

Singh appeared before Melbourne magistrates court on Monday and did not apply for bail. He has been remanded to reappear on 1 October.

Senior Constable Lynette Taylor, Senior Constable Kevin King, Constable Glen Humphris and Constable Josh Prestney died when a truck crashed into them while they were dealing with a Porsche driver in an emergency lane on Melbourne’s Eastern Freeway at Kew.

Ashton previously said the truck moved from one of the freeway’s traffic lanes into the emergency lane where the police cars were parked. The truck slammed into the back of the highway patrol car at about 100km/h.

Singh looked down at his feet throughout the brief court hearing.

Singh’s defence lawyer, Steven Pica, said Singh would require psychiatric treatment while in custody, and was “stressed and saddened” by the result of the crash. Pica said Singh had previously suffered from panic attacks and anxiety and was believed to have had an undiagnosed psychological disorder throughout his life.

The prosecution requested the hearing be delayed until October due to the time required to compile a detailed brief, including reconstruction of the accident and obtain reports from overseas.

On the night of the accident, Singh’s Cranbourne home was searched by police but the results of this warrant have not been made public.

At a press conference on Monday Victoria police assistant commissioner for road policing, Libby Murphy, said two more search warrants had been executed at addresses related to the company Connect Logistics, whose logo was on the side of the truck Singh was driving.

Murphy said these were residential addresses in Croydon and Frankston and were in relation to national heavy vehicle laws.

“What [the heavy vehicle laws] are there for is about a chain of responsibility, so they relate to heavy vehicles that are more than 4.5 tonnes. It’s to ensure that people have responsibilities and companies make sure that … drivers keep to hours and the vehicles are ride worthy,” Murphy said.

Victoria police’s heavy vehicle unit is conducting this portion of the investigation. Murphy did not rule out the possibility of more charges being laid.

Murphy went through police training with Taylor 31 years ago and commended those who helped and comforted her at the scene.

“I don’t want to take it away from the four people because each of those place members had someone who truly loved them within the organisation … obviously I knew her personally, but that doesn’t take away from Kevin, Glen or Josh. Each of them was loved dearly by people in our organisation.”

The driver of the Porsche, Richard Pusey, has been charged with nine offences, including driving at a dangerous speed, reckless conduct endangering life, failing to render assistance and drug possession.

The court heard Pusey allegedly filmed himself taunting Taylor as she lay dying.

Pusey allegedly walked up to her and said: “There you go. Amazing, absolutely amazing.

“All I wanted was to go home and have my sushi and now you’ve fucked my fucking car.”

On Monday a woman claiming to be Pusey’s mother contacted Melbourne radio station 3aw. She said the family was estranged from Pusey and were ashamed of his alleged actions.

“We would like to say that we are truly devastated by the tragic events that unfolded … we extend our deepest heartfelt sympathies to the families, friends, and colleagues of the four offices that tragically lost their lives.

“We as a family have been estranged from Richard for some period of time. We learned of the horrendous accident on Wednesday. We were incredibly shocked and deeply ashamed by the events that unfolded surrounding the accident and thereafter … And all we can say is we feel the same sense of devastation as the community at this time.”

He also allegedly tested positive for ice and cannabis and was urinating on the side of the freeway when the truck smashed into four officers impounding his Porsche 911.

Pusey allegedly fled, before asking a witness for a ride to his home suburb of Fitzroy. He was arrested the next day. He remains in custody on remand.