The 72-year-old's sentencing hearing was slated to take place Dec. 21, but was delayed when the judge raised an issue about some of the details in the pre-sentence report regarding substance abuse and addictions.
Ontario Court Justice Andrew Buttazzoni referred to information that indicated medical staff had concerns about nine prescription medications Duplin was taking when he was remanded in custody for the June 7, 2016 assault and adjustments were made.
He adjourned the matter to the new year, so defence counsel Jennifer Tremblay-Hall could explore the prescription issue.
On Monday, she told the court she has contacted a toxicologist who is taking a look at the material.
"The earliest he can give a a verbal response is mid-February," she said.
Buttazzoni put the matter over until Feb. 27, at which time a date will be set to either hear the motion to re-open the proceedings or to complete the matter.
Duplin was convicted of attempted murder on Nov. 30 for a brutal machete attack on his nephew Larry Paquette.
When he found the accused guilty of the offence, Buttazzoni called it a "vicious, unprovoked and life-threatening" assault on the victim, who had described his attacker as his "favourite uncle."
Paquette was asleep in a recliner at his Aweres Township when Duplin repeatedly slashed him in the head with a machete, fracturing his skull.
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