LAVAL, Quebec (AP) — The former long-time mayor of Quebec’s third-largest city was arrested yesterday in connection with a corruption scandal.

Robert Lafreniere, head of the anti-corruption unit, said former mayor Gilles Vaillancourt is one of 37 people who face a variety of charges including fraud, conspiracy, breach of trust and gangsterism charges. Officials have not yet confirmed which specific charges Vaillancourt will face when he appears in court later Thursday. Many of the others facing charges are expected to appear in court in July.

Vaillancourt served as mayor of Laval, a suburb of Montreal, for 23 years before stepping down last November amid a public inquiry into the scandal.

Lafreniere said the investigation targeted the dismantling of an organized and structured network operating a system of corruption and collusion in the provision of public contracts.

“This network was well established in Laval by three distinct groups: entrepreneurs and engineers; facilitators, lawyers and notaries; and a group of individuals including a mayor and a general manager,” said Lafreniere.

“These are extremely serious accusations,” said Lafreniere, adding that investigators met with 150 witnesses, listened to 30,000 wiretap conversations and seized US$481,000 (CA$483,000). “Today’s operation is a testimony of the magnitude of the corruption phenomena we are facing.”

Gangsterism, a charge of committing offenses for a criminal organization, is usually filed against biker gangs, street gangs or mafia mobsters.

People living around Montreal, Canada’s second largest city with a population of 1.7 million, have long assumed a fair bit of corruption existed in the city’s politics, but only recently have they learned the extent of it. The Charbonneau commission, the inquiry looking into the awarding and management of public contracts in the construction industry, was created in the autumn of 2011. The inquiry has become a major source of information to understand how corrupt practices spread so widely across Quebec’s political system.

Vaillancourt, who was nicknamed the “King of Laval” after getting re-elected to the job six times, governed the city during a construction boom.

A former construction boss testified during the inquiry that Vaillancourt received a kickback on contracts. Vaillancourt denies the allegations.

Montreal’s former mayor Gerald Tremblay also resigned last year amid the public inquiry that heard testimony detailing graft and ties to organized crime in the construction industry.