MONTREAL -- Quebec provincial police arrested their own former colleague on Tuesday for allegedly passing along police secrets to organized-crime suspects in Gatineau five years ago.

Since 2016, the Sûreté du Québec (SQ) knew someone might have given out privileged information during a drug trafficking investigation, SQ spokesperson Benoit Richard told CTV News.

They finally arrested a 54-year-old former detective who has since retired.

"We got some leads that there could have been some leaks, and in 2019... the information was taken up by Internal Affairs of Sûreté du Québec," said Richard.

"What we allege is that he gave out some information to a third party that was able to give that [information] to some of the people that were investigated."

Quebec police didn't name the man, with Richard explaining it's not customary to name an accused person until he or she is arraigned in court, which in this case will happen in a month.

However, La Presse reported Tuesday that his name is Marc Vaillant.

The man was arrested Tuesday morning in Gatineau, where he lives, and is expected to face charges of obstruction of justice and breach of trust.

The events date back to 2015 and 2016, when the SQ had an investigation targeting organized crime in the Outaouais region, which includes the city of Gatineau.

"He was not undercover," said Richard. "He was a regular detective," based in the Outaouais.

The drug trafficking investigation was an attempt to crack down at cannabis production in the area. It lasted at least two years and involved more than 100 officers from different police forces, according to an SQ release from 2016.

It ended with 21 arrests in the fall of 2016, including the two men who police said were "the presumed leaders of the large-scale production and distribution of cannabis in the Outaouais region," Yann Maisonneuve and Hugues Mongeon.

Their drug ring had an estimated profit of nearly $4 million annually, police alleged at the time, and involved many of their family and friends.

Despite the extensive property searches and arrests, police ended up feeling that "maybe we found less stuff than we should have found," said Richard, after getting wind of a potential leak.

He said he didn't know whether the ex-detective is accused of profiting off leaks, but the charges make clear that the SQ are alleging he did it intentionally and "gave out privileged information that he knew was privileged."

The ex-officer "will be accused, among other things, of having willfully attempted to obstruct, hijack or thwart the course of justice and of having committed a breach of trust in relation to the duties of his office," the SQ wrote in their release.

"The charges against this ex-investigator relate to inside information that he knowingly passed on to suspects targeted by a criminal investigation."

He is scheduled to appear at the Gatineau courtouse on Nov. 17 to face the charges. 

The criminal case has been handed to Quebec's Crown prosecutor, the SQ said. But the force's internal affairs department has also pledged to be transparent about the steps it took in this case.

Such cases are "uncommon" and "always upsetting," said Richard, but as far as other officers are concerned, the important thing "is that when we get those kinds of information, it's to take action."