An Ontario drug dealer has been sentenced to 10 years in prison after a man who believed he was buying cocaine ended up getting fentanyl instead -- and died from an overdose.

Brantford, Ont., drug dealer Andrew Allison, 35, accidentally gave a bag of powdered fentanyl to Anthony Mirco, 56, last fall, court heard.

Mirco thought he had purchased cocaine and he went into a coma after snorting some of the powder, court heard. He died in hospital four days later.

“There was never any intention to harm this person,” said Allison’s lawyer, Lauren Wilhelm. The judge agreed, calling it a case of an “incompetent drug dealer.”

Mirco’s son, Tyler Mirco, says that he was proud of his father despite him having “made the wrong choice.”

“That guy made the wrong choice as well,” he added, referring to Allison. “And that’s what he’s going to jail for.”

The 10-year sentence was less than the 12 years the Crown sought but more than the six years Wilhelm had proposed for her client.

“The hardest thing for Andrew to deal with is having made a mistake that ended so tragically,” she said.

Mirco has used his father’s death as a reason to move forward in his own life. He has signed up as a volunteer first responder with St. John Ambulance.

“I’ll be able to deal with things like people on fentanyl so it’s definitely encouraged me to do that,” he said.

With a report from CTV Kitchener’s Nicole Lampa