A man who was fatally shot on a south-east Queensland farm received a "threat on his life" by a colleague who "thought he was a spy" in the months before his death, the coroners court has heard.
Jeffrey Brooks died after suffering a single gunshot wound to the chest, in what was initially ruled a workplace accident in Beenleigh in March 1996.
The 24-year-old marine biologist, who was doing research on a crayfish farm, including a feasibility study, was found slumped over a shotgun inside a work ute at the property.
A coroner is re-examining the circumstances surrounding his death, after an earlier inquest, concluded in 1998, was unable to rule out foul play.
The re-opened inquest being held in Brisbane has already heard Mr Brook's family believe their son, who they stressed took gun safety seriously, could not have accidentally shot himself.
The court heard they suspect three workers — farm manager Johannes Geiger, his wife at the time Regine Kjellerup, and farmhand Graeme Lloyd — were involved in his death.
Mr Geiger and Ms Kjellerup have previously denied the claims and on Wednesday Mr Lloyd told the court he had "absolutely not" killed him, but "wouldn't have a clue" if anyone else did.
"If I could help … I would," he said.
The court heard Mr Lloyd had been working on the farm on the day of the shooting, but he told the court he was driving a noisy "feeder van" and did not hear any gunshots.
During the afternoon Mr Lloyd discovered Mr Brooks' body and told the court that image had been "stuck in his mind" ever since.
"It's not something I like to see," he said.
He admitted to being scared of Mr Geiger and told the court he once "turned" on him.
'Heavy vibe' on farm prior to death
Another colleague who worked in the head office in New South Wales, Paul Stewart, gave evidence about the lead up to Mr Brooks' death, including suspicions stock was being stolen.
"There were concerns about sales happening that head office didn't know about," he said.
He told the court his employer hired a private investigator to look into this but could not recall exactly when that was.
The court has already heard before he died Mr Brooks told friends and family he was being threatened by his colleagues over his knowledge about theft and fraud.
When asked about the relationship between everyone who worked on the farm, Mr Stewart said there was "tension" and a "heavy vibe".
"They made things difficult for [Mr Brooks]," he said.
Mr Stewart said he believed Mr Geiger "thought he was a spy" and "questioned everything" Mr Brooks did.
On the day of the shooting, Mr Stewart told the court he spoke with Mr Brooks over the phone, and the called ended with him saying he had to go and "curiosity killed the cat".
When asked what this meant, he said Mr Brooks was "really paranoid" as he had recently discovered a "black book" which "indicated there were sales going on".
'Hindsight is a beautiful thing'
The court heard Mr Stewart never told police about this conversation, and first mentioned it in a statement in 2001 to a private investigator, then elaborated on it in later media interviews.
When asked why he did not tell officers when he was initially interviewed, he said he was "totally rattled" and was affected by the death for some time.
"I struggled putting two words together … It was later on things came to me," he said.
The court heard when he found out about the shooting, he drove himself and his employer Greg Milham to the farm and police were called on the way.
Mr Stewart said Mr Milham told the operator: "I'd like you to treat this as a homicide because [Brooks] had been threatened."
"I remember those words vividly," he said.
A former youth group leader, Allen Eggins, also testified about a conversation he had with Mr Brooks in late 1995 about receiving what he perceived as a "warning" from Mr Geiger.
"He told me about an incident where a shot was sort of fired over his head … He thought it was a threat on his life."
The court heard this information was also never provided by way of a police statement, but Mr Eggins had given an interview for a podcast.
The inquest continues.
