It's not too late to turn yourself in.

Assistant Commissioner Lammers said there was still a chance to give Mr Forsyth's family some degree of peace.

"The public is entitled to feel a sense of anger, particularly if they're closely related to the family, that there is somebody for whatever reason who has done this and has not come forward," Assistant Commissioner Lammers said.

"If that person is still alive, there is still an opportunity for that person to come forward and tell their side of the story," he said.

Mr Forsyth, 17, was run down and killed by a blue panel van on Kent Street in Deakin in March 1987, as he walked away from an 18th birthday party with his friends.

There was early evidence - later retracted - that the van swerved at Mr Forsyth, and that threats had been made against Mr Forsyth's life. Police in other branches were also receiving intelligence that the death may have been deliberate.

Despite that, detectives were refusing to consider it suspicious from an early stage, telling one witness they wanted an "open-and-shut case", and delaying the involvement of the criminal investigations branch and the media in the crucial hours after Mr Forsyth's death.

Inconsistent and changing statements from witnesses were not properly explored, and proper supervision and guidance of the investigation was not set up until five days after the hit-run.

Assistant Commissioner Lammers took a personal interest in the case last year, and looked over the evidence himself, before instigating a review by leading crash investigator John Ruller.

Mr Ruller recommended against opening a new homicide investigation, and said the only way the case could be progressed was for the driver or someone with first-hand knowledge to come forward.

He found there were deficiencies in the investigation, but that the at-scene investigation was sound, and that police had now exhausted all leads.

Mr Ruller said the current evidence would likely only support a charge of failing to stop, rather than the more serious culpable or negligent driving.

He found the reasons that the driver did not stop were unlikely to be known, but noted it was possible they were drunk or unlicensed.

Assistant Commissioner Lammers said the driver still had the opportunity to come forward and tell their side of the story.

"If it is as the reviewer has concluded, that it's possible he was either intoxicated at the time or was unlicensed, or there was some other reason that he didn't stop back then, surely with the passage of time there's an opportunity for him or her to come forward and talk to us about it and provide that extra little bit of peace for the family," he said.

Interest in the case was reignited in 2012, after Fairfax revealed irregularities with the initial investigation of Mr Forsyth's death.

One of Mr Forsyth's school friends, Mark Plows, re-emerged to allege he was bullied into staying quiet about information he had about a panel van driver, who was at the party, and tried to drive back past the scene.

That suspect has since been ruled out in Mr Ruller's review of the case, although Mr Ruller did not speak with Mr Plows.

Further progress in the case has been complicated by the loss of physical evidence during a flood at police's old exhibit management centre.