That's the determination a Sudbury judge must now make after hearing evidence, including testimony from an expert witness, and submissions from the lawyers at the Sault Ste. Marie man's trial.
Ontario Court Justice Andrew Buttazzoni indicated Friday the he expects to have his decision in about a month.
The closing arguments made by prosecutor David Didiodato and defence counsel Jennifer Tremblay-Hall centred on whether the accused had formed a specific intent to kill — the mens rea required for the offence of attempted murder.
Duplin, 71, is charged with assault with a weapon, aggravated assault and attempted murder in connection with the June 7, 2016 attack.
In February, Larry Paquette told the court how he awoke that evening to find his "favourite uncle" standing over his recliner and striking him "really hard" with a machete.
The attack occurred in the 55-year-old man's Rupert Acres Drive home after the pair had spent the day drinking beer and smoking marijuana.
Paquette described how he put up his hands to defend himself and asked Duplin "what the f** k are you doing?"
The older man replied "I'm going crazy."
He said after pushing Duplin away, he told him to call the ambulance, and lost consciousness.
Paquette testified that he woke up a few days later in Sunnybrook Hospital in Toronto, with injuries to his head and both hands. A finger on his left hand had been cut off.
He told Buttazzoni that he had been hit 22 times.
On Friday, Tremblay-Hall called Duplin's attack on his nephew "an impulsive act" as opposed to a considered decision.
The machete was there in the home and there was no evidence of planning or motivation. There was no anger between the two men, she said, pointing to Paquette's evidence that nothing had seemed to precipitate what had happened.
"He loved Duplin and Duplin loved him back. There was no issue that day."
The defence noted that when Paquette asked Duplin what he was doing, his uncle replied "I'm going crazy," not "I hate you, I'm going to kill you."
Tremblay-Hall said her client stopped striking Paquette and went to get help when his nephew told him to do so.
"This suggests the impulsivity of the act," she maintained. "That's not an indication of someone who planned to kill somebody."
The Crown must prove specific intent and "there is evidence to the contrary," especially the expert evidence provided to the court by a Sudbury neuropsychologist, Tremblay-Hall said.
Dr. Matias Mariani was the only witness called by the defence during the trial and he "clearly testified" that Duplin, because of his cognitive abilities and intoxication, didn't foresee the outcome of his actions, she said.
Didiodato countered that the "specific intent is overwhelming in this case," and when all the factors are examined, it can be concluded that Duplin intended to kill Paquette and he should be found guilty.
This was "an unprovoked, relentless attack on a sleeping individual," the assistant Crown attorney said, suggesting nothing can be inferred beyond specific intent.
A machete, an "extremely lethal weapon," was used in the attack, that primarily targeted Paquette's head, causing four fractures to his skull and a large laceration to his forehead, he said.
There also were multiple blows to the victim's abdomen and lacerations to his neck.
"The head is the most vital area of the human body," Didiodato told the court. "The neck and the abdomen are next."
He noted there were dozens of strikes — "an extreme number" — as well as repeated blows to the skull.
"There is nothing defensive about this. It was an attack carried out on a person in a most defenceless position — asleep in a chair."
Tremblay-Hall replied that the prosecution was asking the court to infer specific intent from circumstantial evidence.
"The Crown is asking you to speculate that he (Duplin) had a specific intent to kill Larry based on a brutal attack," she told Buttazzoni.
On Friday, Duplin pleaded guilty to the assault with a weapon count so that a pre-sentence report can be prepared.
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