The Royal Canadian Mounted Police made the arrests as part of a 4-year-old investigation into the construction industry in the province, The (Montreal) Gazette reported.
The four men, ranging in age from 43 to 60, face charges of conspiracy, fraud, forgery and breach of trust by a public officer related to contracts worth hundreds of millions of dollars, police said.
The accused are Antonio Accurso, Francesco Bruno, Francesco Fiorino and Adriano Furgiuele, the Gazette said.
In April, Accurso was arrested in a separate investigation and charged with fraud, conspiracy, influence-peddling, breach of trust and defrauding the government pertaining to the awarding of $40 million worth of construction contracts, the reports said.
RCMP Cpl. Luc Thibault said a fifth man was being questioned Thursday, but no charges had been filed, the Canadian Broadcasting Corp. reported.
Others were still being investigated, police said.
The four men charged will appear in court in Montreal for their first appearances Sept. 19, the reports said.
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