A man has been found guilty of criminal negligence causing the drug-related death of a 17-year-old boy in Saint John more than three years ago.

Gavin Adams disappeared on Dec. 14, 2013. Snow removal crews found his body two days later in a parking lot in the city’s north end.

Investigators believed Adams had been given a hallucinogenic drug called 25-I which caused his death, and Richard Valiquette was arrested and charged with manslaughter and criminal negligence causing death.

The manslaughter charge was later dropped.

Justice Frederick Ferguson convicted Valiquette of criminal negligence causing death Monday morning in Saint John’s Court of Queen’s Bench.

The family of Gavin Adams attended Valiquette's trial in fall 2016, and they arrived for the judge's verdict on Monday.

"We've gone through a lot of steps, but it is a step, an important step, this decision to find people responsible for these crimes and we think it will go a long way to help," said Gavin’s father, David Adams.

The family received a 164 page document outlining the facts of the case and the accusations against Valiquette.

Justice Ferguson noted that there are a number of legal tests that have to be satisfied in order for there to be a conviction of criminal negligence causing death. Among the questions the judge said he was trying to answer was whether the conduct of Valiquette showed a wanton disregard for the life and safety of Gavin Adams.

"There is no other conclusion that can be reached than that Mr. Valiquette's actions, in giving the drug 25-I to Gavin Adams, contributed significantly to his death," Justice Ferguson said in his verdict.

It was the decision the Adams parents wanted to hear.

“There's no expectations for the future. You just deal with things as they come and I think in your mind, you have what Gavin would have wanted us to do and what would be good for society as a whole," said David Adams.

Richard Valiquette left the courthouse accompanied by family and friends and did not respond to media questions.

He is due to be sentenced at a later date.

With files from CTV Atlantic’s Mike Cameron.