MONTREAL - More than 90 tax investigators carried out multiple raids on Quebec's biggest construction empire Wednesday in the latest blow to troubled magnate Tony Accurso.

Revenue Quebec visited nine locations in Montreal and suburbs to the north.

The targets included insurance companies and accounting offices.

Revenue Quebec said the operation was aimed at "gathering evidence that will be analyzed to determine if (tax) laws were violated."

Accurso and his family run a multi-billion-dollar empire that's involved in many of Quebec's biggest construction projects, including the sprawling McGill superhospital that will be the largest in Canada when it opens in 2015.

A media report revealed that Accurso has landed $1 billion in public contracts since 1990, mainly from Transport Quebec, but his business practices have landed him in hot water recently.

Accurso has been arrested twice this year, once for alleged tax evasion and a second time on corruption charges.

His two main construction firms were cited in 2010 for $4.1 million in back taxes.

Accurso also made headlines in 2009 after several Quebec politicians were found to have vacationed on his 120-foot luxury yacht.

Quebec has since cancelled 17 contracts worth $21.2 million that had been held by Accurso companies.

But one of his biggest holdings, Simard-Beaudry, continues to work on the superhospital west of downtown Montreal.

The project became embroiled in controversy last month when anti-corruption investigators raided the hospital's downtown administrative offices for alleged contracting irregularities.

It's not clear if the raids last month targeted Accurso's company.

His name also came up this week at an inquiry into corruption and collusion in the construction industry.

Former excavation contractor Lino Zambito said Mafia don Vito Rizzuto once mediated a dispute between him and Accurso.