These circumstances could not have been more different from those of his pursuers on the task force, composed of local detectives, career federal agents and government prosecutors like Mr. Tiscione. The task force, however, had a lead, and within a year of receiving the woman’s complaint, the Queens dealer, who was caught selling drugs, was facing prosecution and became an informant.

One piece of the information he provided was the alias of his Canadian supplier, a man known as Cosmo, whose name, he said, derived from his residence in the Cité Cosmo, a luxury condominium in the Montreal suburb of Laval. Mr. Tiscione and his team eventually learned Cosmo’s real name by eavesdropping on his network with wiretaps and by putting pressure on other dealers, but they were unaware of his lengthy history until they contacted the authorities in Laval. The Canadians described Mr. Cournoyer as a seasoned trafficker whose criminal career had begun at age 18, when he and his brother Joey were arrested with a stash of 11 marijuana plants at their apartment.

In 1998, Mr. Cournoyer pleaded guilty in that case and was sentenced to probation. But two years later, he was caught again, selling marijuana out of his Jeep at the Kanesatake Mohawk reservation, a half-hour’s drive from Laval. Although he pleaded guilty in that case, too, he escaped a serious prison term. He was arrested, for a third time, only 12 months later. On that occasion, Mr. Cournoyer had checked into a Hilton in Toronto, planning to sell 10,000 Ecstasy pills to a customer for $65,000. The customer turned out to be an undercover agent. As he tried to flee, Mr. Cournoyer was captured, despite, court papers say, brandishing a handgun loaded with armor-piercing bullets.

Image Mario Racine Credit... Filed with United States District Court, Eastern District of New York

The lesson he learned from prison that time was perhaps not what the authorities intended. As Mr. Tiscione would later write in a legal memorandum, “Determined to never again be found in the compromising position of physically touching narcotics, Cournoyer began expanding his roster of associates and installing additional layers of subordinates between himself” and the drugs.

Among those subordinates was Mario Racine, a fellow Canadian, whom Mr. Cournoyer sent to the United States in the early 2000s, court papers say, to manage the increasingly giant loads of marijuana flowing across the border. Mr. Cournoyer had met Mr. Racine through Mr. Racine’s sister, Amelia, the lingerie model whom he dated for several years. Mr. Racine organized the outfit’s East Coast distribution. The biggest distributors were generally given up to 200 pounds of marijuana at a time, with brand names like Sour Diesel, which they then resold in pound quantities to smaller retail salesmen.

Another top lieutenant was Patrick Paisse, a one-legged Québécois who helped Mr. Cournoyer arrange a deal with the Hells Angels to drive huge loads of pot from fields in British Columbia and greenhouse factories equipped with charcoal air filters and off-the-grid power systems across the border, hidden beneath the tarps of tractor-trailers.