Police are treating it as a homicide and believed he was killed the day before Christmas Eve in the afternoon.
Detective Superintendent Dave Hutchinson told APNZ today that a Crimestoppers bus was set up outside the crime scene on the same day of the week, at the same time as the killing, to try and get more information from people in the area.
"We just wanted to remind everybody going past that this did occur and if they have seen something on that particular Friday that they haven't told the police to come forward."
Between 10 and 20 detectives working on the case every day, he said.
Police were not at a dead end in their investigations, but Mr Hutchinson could not say what lines of inquiry they were following.
"We've got lots of information that's come in over a period of time so we have that information obviously that we have to run out so certainly not at a dead end."
Today's appeal was to make sure the killing was not forgotten, he said.
"We are still of the belief that there are people out there who know things that they haven't told us, so we just want to reinforce the fact of what occurred and appeal to them to come forward."
Detective Inspector Brian Swan of Gold Coast police last month said a "scorned lover" could have been involved in the murder and an affair with a married woman was among the possibilities.
"A number of people have come forward who knew Mr Williams, a number of females."
But he dismissed reports Mr Williams had been with hundreds of women.
"I can't disclose the exact number of people who've come forward ... it certainly is nowhere near that number," he said.
"One thing is that we're finding out through our investigations is that Mr Williams is a very popular man, very well-liked, highly respected and a very talented man.
Mr Swan said it was possible more than one person was involved.