Crash investigators say the driver of a truck which could have killed a Kirrawee motorcyclist may not realise he was involved in a collision.
They have released images of a white, flatbed truck seen driving near the crash site at Waterfall on Wednesday.
Paul Snepvangers, of Kirrawee, was found dead next to his Yamaha in McKell Avenue, Waterfall, on Wednesday afternoon.
Traffic commander, Superintendent Stuart Smith, said crash specialists had examined the incident.
"What we have developed as a result of that investigation are tyre imprints and impressions from the scene and CCTV footage," he said.
"Police are anxious to speak with the driver of what we believe is a white Hino vehicle, possible aged between 1995 and 2000.
"It's dual-wheeled and of particular note is the space between the cabin and the tray.’’
Mr Smith said that although leaving the scene of a fatal accident was a serious crime, the truck driver may not realise what had happened.
"Police specifically want to talk to the driver ... who may or may not know he was involved in an accident on Wednesday afternoon," Mr Smith said.
"We need to give the family closure. They are good people, they just need to know what happened."
Mr Snepvangers's daughter, Jhoanna Parker, joined the call for witnesses.
"The police and our family are urging for the driver to come forward," she said.
"My father's best mate was only a few kilometres ahead of him and recalls seeing work vehicles of a similar description in the vicinity, parked on the side of the road of McKell Avenue, Waterfall.
‘‘We are urging them to help come forward with the investigation.
"Please come forward."
Crime Stoppers: 1800 333 000.