To show police he was upset after a woodchipper death, Gregory Lee Roser thought of his dead mother, a court has heard.
Roser, 63, and Sharon Graham, 61, have pleaded not guilty to murder after Bruce Saunders died while working on a property north of Brisbane in November 2017.
The jury has retired to consider its verdict in week five of Roser's trial before Justice Martin Burns in the Brisbane Supreme Court.
The Crown alleges Graham asked Roser and another lover Peter Koenig to kill her ex-partner Mr Saunders, 54, and make it look like an accident in a bid to claim his $750,000 life insurance.
Footage has been shown of Mr Saunders' legs protruding from the chipper at the Goomboorian property near Gympie after clearing trees with Roser and Koenig.
Roser does not dispute Mr Saunders was murdered but says Koenig is the killer, claiming he "shamefully" helped dispose of the body.
However, crown prosecutor David Meredith told a jury they should have real doubts about anything Roser says, citing a police recorded conversation from January 2018.
In the recording Koenig asked Roser how he reacted to being shown gruesome photographs of the murder scene during a police interview, suggesting his facial expressions would be analysed.
"When they showed me the photographs ... I started getting upset about the photographs and I started thinking about my dead mother," Roser said.
Mr Meredith told the jury: "He had to sum up concern about his dead mother so he could show apparent distress at seeing Bruce's body.
"(And) remember ... he helped ... put Bruce's body in the chipper so it would come as no surprise to him those gruesome photographs."
Roser earlier told the court that Graham had come up with several plans over several months to kill Mr Saunders but he refused.
However Mr Meredith said: "He didn't make it clear that he wasn't going to do it, he just rejected them on the basis that the plans were stupid.
"Why would she continue to approach him unless she thought he was a candidate to do it (kill Mr Saunders).
"He might have been rejecting the means but not the ends."
Roser told the court that Graham eventually came up with a plot to kill Mr Saunders while clearing trees, incorporating the chipper but again he refused.
However Mr Meredith told the jury Roser believed the accidental death option was more sensible if they are trying to successfully claim Mr Saunders' money, saying "she (Graham) can't collect if she is a murderer".
He said Roser was an obvious candidate to be the killer because he was desperate for a relationship and keen to please Graham, rejecting claims that Koenig was responsible.
The quiet, pony-tailed Koenig denied he was a killer when he gave evidence earlier, claiming Roser had bludgeoned Mr Saunders with a metal bar before they fed the body through the chipper.
Koenig pleaded guilty to accessory after the fact to murder this year.
Roser told the court that he only agreed to help dispose of the body because he feared Koenig who he claimed had Mafia connections.
"Peter Koenig part of the Mafia? You have seen him, he doesn't look like a criminal mastermind at all," Mr Meredith said.
Roser said he feared he would "end up like Bruce" if he didn't help Koenig with the body.
"How could he possibly think that Koenig is going to kill him too and put him through the chipper?" Mr Meredith said.
"Would anyone believe there are two accidental deaths? To adopt a famous line from Oscar Wilde, to lose one friend through a woodchipper is unfortunate, to lose two is incredible."
Graham has successfully applied for a separate trial.
