The Surete du Quebec anti-corruption task force known as Operation Hammer slammed down on seven people Thursday, including former Boisbriand Mayor Sylvie St-Jean who was arrested at her home in the morning.

St-Jean and the other six accused now face a total of 28 charges related to fraud, corruption and extortion.

Others arrested in the raid include: Giuseppe Zambito, President of the Infrabec construction company, and Vice President Lino Zambito; former Boisbriand City Councillor Claude Briere; Rosaire Fontaine, an engineer at BPR-Triax; France Michaud and Gaetan Morin of the Roche engineering consulting firm.

In 2010 a Radio-Canada investigation revealed the mayor had awarded most of the Boisbriand city contracts to the Zambitos' Infrabec construction company.

According to the SQ, the company was the sole bidder for the local sewer treatment plant. That project saw costs nearly double during construction, and there are charges that the firm intimidated other potential bidders

Operation Hammer chief Denis Morin said Thursday that gifts and travel worth thousands were given in exchange for contracts.

The seven were released Thursday under promises to appear in St. Jerome court to face charges.

The SQ's Operation Marteau, or Operation Hammer, has 40 full time investigators and a budget of $26.8 million to be spent over three years. Since its inception it has carried out 80 search warrants and made 14 arrests.

-With files from Canadian Press