The 47-year-old married driver from Lowood, near Ipswich, was thrown from the cab of his vehicle after it smashed into a guardrail and rolled on the southbound lanes of the road at Eagle Farm.
The truck, which was coming from Bowen and headed for the Rocklea Markets, skidded on its roof, crushing the cab and splitting open the tandem trailers.
Pallets of pumpkins and boxes of capsicums were strewn over the roadway.
Police want to speak with anyone who might have also seen the alleged incident.
They also plan to examine footage from traffic cameras along the road and at the Gateway Bridge toll booth.
Queensland Police Commissioner Bob Atkinson earlier said if the theft claim was correct, it was a “poor act”.

He said if evidence was found that supported the claim and led to a suspect, that person could be charged with stealing.
“On the face of it, it is a despicable act, particularly if assistance was required,” he said.
RACQ spokesman Gary Fites said if the claim was proven true, he hoped the incident was a rare and disappointing exception to the way most Queensland motorists look out for each other.
“If it is true, it is pretty callous. It surprises me,” he said.
“Everyone has a duty to render assistance to injured motorists until help arrives.”
Investigators are yet to determine the cause of the crash, which occurred in an area where extensive roadworks are under way as part of the Gateway road and bridge duplication.
Police said it appeared the truck failed to take a bend.
They are investigating whether fatigue or speed were involved.
Transport Workers Union Queensland secretary Hughie Williams questioned whether the Gateway in its current state was suitable for such B-double semi-trailers.
Yesterday’s accident, which closed parts of the motorway for most of yesterday, was the latest in a string of recent truck incidents on the road.
“I think it is OK for prime-movers but perhaps drivers of B-doubles should take a different route,” Mr Williams said.
- with AAP