There will not be an inquest into the 2010 prison murder of Melbourne gangland figure Carl Williams, a coroner has ruled.

State Coroner Judge Ian Gray said Williams’ death had already been the subject of inquiries from government agencies and other bodies.

Judge Gray said there was no systemic defect he could identify which warranted further probing, and which hadn’t already been the subject of investigation.

“Ultimately I do not identify a legitimate coronial purpose that is likely to be served by holding an inquest,” he said on Wednesday.

The Williams family had requested an inquest, but the call was rejected by the police chief commissioner.

Williams’ father, George Williams, was in the Victorian Coroners Court for the ruling.

Williams was clubbed to death by another inmate using part of an exercise bike.

The Victorian Ombudsman later found the prison system had failed in its duty to protect the high-profile prisoner.

Judge Gray said Williams’ death was one of the most investigated incidents in Victoria’s history.

The extensive and comprehensive investigations included the ombudsman’s inquiry.

Fifty-five of the 57 recommendations made by his inquiry had already been implemented, Judge Gray said.

Other inquiries included the criminal trial and conviction of Williams’ killer, a Victoria Police task force review, an Office of Correctional Services review, and an Office of Police Integrity probe into Williams’ handling.

Judge Gray said Williams’ criminal and personal history were not factors in his decision.

Under law, if a person has already been charged with an indictable offence over a death, it is not mandatory for a coroner to stage an inquest.

A coroner also must avoid duplicating inquiries unnecessarily, the judge said in his ruling.

Neither George Williams nor Williams’ ex-wife Roberta Williams spoke to reporters as they left the court.