SUDBURY, ON -- A four-year long investigation into the theft of more than $16 million from a major mining supply company led to three Montreal-area men being charged.

Greater Sudbury Police issued a release Wednesday detailing the results of the investigation, which was conducted jointly with the RCMP.

"In 2008, our service entered into a joint forces fraud investigation with the RCMP, because the complainant was the Sudbury Atlas Copco," said Meghan O'Malley, media relations officer for Greater Sudbury Police.

"They had reported that there was an internal fraud that had happened when two of their senior executives conspired with the company's health-care provider to increase monthly billing, and also to produce fraudulent invoices."

Two former executives, Dirk Plate, 68, and 66-year-old Leo Caron, 66, were arrested in Montreal and returned to Sudbury for bail hearings.

An arrest warrant has been issued for Paul Caron, 68, who worked for Atlas Copco's health-care provider.

O'Malley wasn't sure if Paul Caron and Leo Caron are related.

Court records indicate that Leo Caron lives in Montreal, Plate in Dorval, Que., and Paul Caron in Sherbrooke, QC.

The RCMP was tipped off to the alleged fraud in April 2008.

"Because it was such an extensive investigation involving so much money, it takes a lot of legwork and, obviously, with two separate police agencies being involved, a lot of paperwork and a lot of paper trail to be following," O'Malley said.

"Because of the extent of the fraud, the amount of money it involved, it did take quite some time to come to this resolution."

In a lawsuit filed by Atlas Copco, the company alleges the scheme was concocted in Sudbury in September 2002, put in place in early 2003 and carried on until at least 2006.

According to the lawsuit, former employees David Hillier, along with Plate and the Carons, came up with the scheme together.

The suit alleges the three former executives gave illegal bonuses and advances not only to themselves, but to as many as 65 others in a bid to keep them quiet.

None of the allegations contained in the lawsuit have been proven in court.