Jonny Cindric was one of three teenagers who watched as the 17-year-old was run down by a Holden panel van on Kent Street in Deakin in March 1987.

Fresh revelations on the cold case, published in the The Canberra Times last week, suggest the early investigations into the hit-run killing were flawed.

Mr Cindric, then just 16, says he will never forget the night he watched his friend die.

''I've got over it, but you never really forget it, you know what I mean?'' he said.

The witness was drinking on the night, but said he gave police a good description of the Holden panel van believed to be responsible, and initially told them he saw it veer towards his friend before impact.

But his evidence was being dismissed by a Criminal Investigations Branch detective working on the case one week after the hit-run, court documents show.

The detective was speaking with another friend of Mr Forsyth's, Barry Treloar, who came forward on March 7, 1987, to tell police he feared the van had deliberately mowed down the 17-year-old.

During that discussion, the detective reportedly told Mr Treloar that two of the witnesses, including Mr Cindric, could not possibly have seen the van veer towards the victim.

He said the pair were walking 50 metres ahead of the victim when he was hit by the panel van.

The detective went on to say there were no suspicious circumstances and that he wanted an ''open and shut case''.

But Mr Cindric, the only witness still living in Canberra, said the detective's claims were simply not true.

He said he had repeatedly told police he was walking 100 metres behind Troy when the collision happened, and saw the ordeal unfold.

He said he ''wouldn't have a clue'' why the detective was claiming he had not seen anything.

''It was me, Troy, Jamie and Chris who decided to walk home,'' Mr Cindric said.

''We were walking home and then Troy was about 100 metres in front of us or so,'' he said.

''He went to cross the road … and then got hit by the car, we ran over to him to see if he was OK or not.''

Mr Cindric later changed his statement because he said he was not 100 per cent sure whether he had seen the van veer towards the victim.

He said no one, neither his family nor the police, pressured him to change his statement.

''They [the police] came round to my house, they read through the statement again, and they said 'would you like to change anything?','' he said.

''When I first saw it, I thought it looked like it swerved.''

''But then I wasn't sure if it did or not, so that's why I said I'm not 100 per cent sure.''

Mr Cindric said he thinks it is strange that the van was never found. ''I thought it would happen fairly quickly,'' he said.

''We thought within a couple of months they'd find the car, but time dragged on, and they just never [found it],'' he said.

He said the three witnesses all gave a good description of the van, and said it was not an overly common type of car at the time.

''We didn't get the number plate of the car, but we thought it was a pretty good description, they could have tracked something down,'' Mr Cindric said.

''They said they went through all the cars, tracked them down, all the cars and the people, but they didn't really tell us much about that,'' he said.

He even underwent hypnotherapy to try and help jog his memory of the number plates, at the request of the police.

Mr Cindric said he would participate in any new coronial inquest into the death.