Police interviewed Joseph James Landry, 67, a week after Boudreau disappeared. Boudreau's overturned boat was found at the mouth of Petit-de-Grat harbour early on the morning of June 1, 2013.
At the time of the taping, Landry had just been charged with second-degree murder. He has since pleaded not guilty.
Landry repeatedly maintains his innocence in the taped recording.
Finally, in a low voice, Landry says he fired four shots at Boudreau's boat. He also admits to running over Boudreau's boat and later offers to take officers to the gun he used.
"I wanted to destroy him," Landry says. "I was seeing black. I was so mad."
Landry says he regrets the killing, but adds that someone had to do it. He says Boudreau had been making fun of him for 15 years and threatened to burn his house.
"I regret it," he tells an RCMP investigator. "I told you the truth. It's all over now."
The Crown has told the jury that Landry used a fishing gaff to drag Boudreau out to sea.
The body of 43-year-old Boudreau has not been found.
The jury will continue watching police interviews on Thursday.
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