"We're conducting a more thorough search of the area where the wood chipper was," Wide Bay Burnett District Detective Inspector Gary Pettiford said. "All up there's about 160sq m that we're searching. It's methodical, painstaking work."
They do not believe the property owner, who was away at the time, had any involvement in the incident.
The machine was ruled out as a fault, with Inspector Pettiford confirming that it was set up in such a way that if a user fell, they could not be pulled straight into it.
"Nothing was wrong with the machine, including all safety features," he said.
The incident was originally treated as an accident, with police believing Mr Saunders, from Bundaberg, became entangled in branches before getting dragged into the wood chipper.
"It's just a tragic accident ... there is no suggestion of foul play," acting Inspector Paul Algie said at the time. He had died "within a few seconds".
It was around 7.40pm on Sunday, November 12, and Mr Saunders was mulching branches with the wood chipper when it was just beginning to get dark.
It was his third weekend helping out "as an act of goodwill' to a woman who had been recently widowed.
Working with Mr Saunders on the property, which is around 200km north of Brisbane in a diverse farming district, were two other adult males.
Mr Saunders became caught in the wood chipper and died.
Gympie Police Acting Inspector Paul Algie later said after visiting the property that it was "one of the worst incident scenes I've ever seen".
But after further interviews of the two men and other witnesses, detectives raided the property last month and seized "items of interest".
Inspector Pettiford said Gympie detectives were contacted by people who knew Mr Saunders and had suggested his death might not have been an accident.
