Police have been told the witness saw at least two men, including possibly a Hungry Jack's worker and a Caucasian male aged 16 or 17, fighting in Cruickshank Park about 9.30pm on January 2. That is the same place and time Mr Garg was fatally stabbed on his way to work at Hungry Jack's.

Detective Inspector Steve Clark, of the homicide squad, urged the witness to contact Crime Stoppers. "We haven't spoken to him, the information has come to us third-hand," he said. "[But] an assault around that time is something we are keen to explore as soon as we possibly can. We won't know until we have spoken to the witness how relevant it is."

It is believed the witness is a regular customer of Hungry Jack's.

Detective Inspector Clark said detectives had interviewed Hungry Jack's staff and customers, and members of the public were constantly contacting Crime Stoppers.

"You may have the missing piece of the puzzle that we are looking for."

Information to Crime Stoppers, 1800333000 or visit their website here.