The province's anti-corruption squad is back at work in Laval.

The target this time is, once again, construction and engineering firms in the city north of Montreal.

UPAC refuses to confirm which companies are being investigated, but reporters have spotted police officers searching the firms of Genivar, Dessau, CIMA+, and AECOM.

90 officers started going through company paperwork at 7 a.m., and say they do not expect to arrest anyone although they will talk to witnesses and those considered people of interest.

Several of those firms have had issues with the government and authorities in the past.

The provincial government fingered CIMA+ as being responsible for the collapse of the Viger Tunnel in Montreal last year, and is demanding that it, along with another firm, pay $3.4 million for damages.

Along with a firm controlled by Tony Accurso, Dessau won the ill-fated water meter contract in Montreal as part of the GENIeau consortium. That contract, the most valuable in Montreal's history, was cancelled after it was revealed that consortium partner Simard-Beaudry took then-Executive Committee chair Frank Zampino on a boat trip.

Accurso has since retired from industry.

Last month UPAC raided several other Laval-based companies, including Poly Excavation, Nepcon, Dufresne Asphalt, Construction Mergad, Louisbourg Construction and Simard-Beaudry.

Those raids, as well as several raids on Mayor Gilles Vaillancourt's homes, convinced the mayor to take an extended sick leave two weeks ago.