MONTREAL—After hundreds of dawn raids and the resignations of two big city mayors, the unit most responsible for investigating corruption in Quebec is looking for a new leader.

Denis Morin, the head of the Surete du Quebec’s hammer squad, is stepping down from the unit he has led since its inception in 2009.

The law enforcement half of Quebec’s permanent anti-corruption unit, the hammer squad’s windbreaker-clad officers have spent three years raiding homes, city halls and businesses across Montreal, Laval and a dozen other cities on the south and north shores.

According to Montreal daily Le Devoir, Michel Pelletier is expected to take over the position. Pelletier currently heads the SQ’s organized crime investigative division.

The reasons for Morin’s decision to leave the high-profile job aren’t clear.