MONTREAL — An accountant and two former Revenue Canada officials are among four people arrested Thursday in a $4.5 million bribery scam.

The RCMP said accountant Francesco Fiorino, 54, and two accomplices, former Canada Revenue Agency officials Gennaro Di Marzio, 49, and Nicola Iammarrone, 53, will face fraud charges.

Other charges include corrupting civil servants, breach of trust by a civil servant, and fraud on the government.

The Mounties say the defendants established a tax-evasion system, with clients promised they would pay less tax if they handed over kickbacks.

The RCMP says CRA officials were then offered bribes in order to circumvent tax rules.

The RCMP says a fourth person was also arrested, was being interrogated and could be charged.

The arrests are part of Project COCHE, begun in 2008, which has probed alleged corruption at the Canada Revenue Agency.

The Montreal tax office has been wrought with corruption scandals for years.

In 2010, the revenue agency admitted it fired six employees and suspended three without pay for misconduct dating back to 2008.

The RCMP has linked Mafia infiltration to the tax office, specifically related to interference in corporate filings.

Two of the fired employees are alleged to have helped stash $1.7 million into offshore accounts in tax havens.

A senior tax auditor was beaten up hours after the agency announced the firings and suspensions.

Two years later, in August 2012, the RCMP arrested three men in a tax-evasion scheme, including former federal tax employee Adriano Furgiuele.