About 30 officers from Quebec’s anti-corruption unit (UPAC) raided the offices of the engineering firm Dessau’s downtown Montreal offices Wednesday morning.

UPAC spokesperson Anne-Frederique Laurence confirms the raids are part of an ongoing investigation into the awarding of a scandal-ridden water-management system contract.

This latest raid comes on the heels of three other raids in Brossard, Quebec City and Sherbrooke in recent weeks, all related to the same case.

Former Montreal city executive committee chairman Frank Zampino was forced to resign his post in the Tremblay administration following allegations of irregularities in the awarding of the $350-million contract.

Police say Zampino spent time on contractor Tony Accurso’s yacht and took trips to the Bahamas, Algeria and Las Vegas with people in the city involved in awarding the contracts. Zampino also allegedly accepted paid meals at restaurants as well and was similarly indulged with parties and visits to the Bell Centre.

Accurso and Dessau ended up winning the contract in 2007. The contract was canceled two years later.