A California man has been sentenced to 16 years in federal prison for his part in what prosecutors believe is the largest mortgage modification scam in history, defrauding victims out of $31 million.

Dionysius “D” Fiumaro and his co-conspirators in the scam were in indicted [PDF] in Aug. 2014 on wire fraud charges.

According to prosecutors, the scammers would purchase lists of potential victims: homeowners at risk of foreclosure because they had fallen behind on mortgage payments. They would then email their targets, falsely claiming that the homeowner’s mortgage was currently under review and that the mortgage lender had already considered and approved a modified rate for the loan.

One example email cited in the indictment attempted to mislead the recipient into believing their mortgage would be modified with an interest rate as low as 2%, and directed the homeowner to call the scammers within 10 days or the offer expired.

The telemarketing firm operated by Fiumano received these calls and also used “sales staff” to call potential victims, falsely representing that by signing up with the scheme, the homeowners were retaining lawyers who would aggressively negotiate the modification on their behalf.

The telemarketers also lied to victims of the scam about the costs involved, telling them there would be no up-front fees and that all fees would be paid by the lender.

In actuality, say prosecutors, the scammers collected fees, did not turn them over to the banks, and did not provide legal representation. At best, the scammers did nothing more than fill in an application for a mortgage modification through the government’s Home Affordable Modification Program (HAMP), a process that any homeowner can do on their own for free. In some cases, not even that minimal effort was exerted.

The scam ran for nearly three years before finally being shut down in 2014. Fiumano was the only one of the indictees who chose to go to trial. In May, a federal jury found him guilty of wire fraud and conspiracy to commit wire fraud. In addition to his 16-year sentence [PDF], which he must begin serving by Oct. 17, Fiumano has been ordered to pay nearly $12 million in restitution.

Fiumano’s co-conspirators have all entered guilty pleas to charges of conspiracy to commit wire fraud and wire fraud. They are slated to be sentenced on Nov. 21.

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