Florida Democratic Rep. Alan Grayson lost $18 million in a scheme by a Virginia man that involved over a 100 victims, the congressman’s office confirmed Monday.

The man who ran the scheme, William Dean Chapman, was sentenced Friday in federal court to 12 years in prison. Prosecutors say Chapman used the money to fund a lavish lifestyle including a Lamborghini, a Ferrari and a $3 million home.

In most of the court papers, Grayson's identity is protected -- prosecutors say only that an elected official with the initials A.G. was the primary victim -- but documents twice mention Grayson by name.

Nothing in the court papers suggests Grayson was anything but a victim of the scheme. Grayson, a former trial attorney, said he has had a long record for picking winning stocks, which formed the basis for his personal fortune.

The scheme worked like this: clients would turn over their stocks to Chapman as collateral for a loan, and Chapman would let customers borrow about 90 percent of the stocks' value.

If the stocks did badly, borrowers could walk away and keep the money they were loaned. But if the borrowers' stocks did well, they would repay the loan with interest, and Chapman was supposed to return the stocks to the investor at their increased value.

But, according to court papers, Chapman sold the stocks and had no way to fulfill his obligations if a client's stock portfolio did well.

"That's why (Chapman) is going to prison for a long, long time," Grayson told The Associated Press. "At least in the end, some kind of justice was served."

In Grayson's case, his stocks performed astronomically well while they were entrusted to Chapman and his company, Alexander Capital Markets.

Grayson’s office said Chapman’s lawyers tried to claim the spectacular performance of Grayson's stocks caused Chapman to be unable to uphold his financial obligations to his clients, but prosecutors found that he was actually using the money to fund his own expenses.

In 2007, Grayson had $9.35 million in a stock portfolio that Chapman was supposed to be holding as collateral. In that year alone, the portfolio's value increased by 147 percent, to $23 million, according to a chart in the court documents.

Chapman, of Sterling, Va., pleaded guilty in May but tried at Friday's sentencing hearing to withdraw the plea, saying he felt pressured to plead and that he never intended to defraud.

It is not the first time Grayson, who represents parts of the Orlando area, has lost tens of millions of dollars in a fraud scheme. In 2009, he won a $34 million judgment after filing a lawsuit in South Carolina under federal racketeering laws against a company called Derivium Capital. Derivium's business plan for hedging an investor's stock profile was nearly identical to the plan outline by Chapman.

Grayson said he first entered into deals with Chapman in 2003, well before the deal with Derivium went south, so he had no reason to be suspicious the arrangement.

And he said the loans themselves were a perfectly reasonable way to manage his portfolio, but relied on Chapman and Derivium to hold up their end of the bargain. He disputed that the astronomical returns to which he was entitled caused Chapman's downfall.

"If they had not sold the collateral, it all would have worked," said Grayson, who is generally listed as one of the 20 wealthiest members of Congress with assets of more than $20 million. His financial disclosure forms list holdings in dozens of stocks. His dealings with Chapman preceded his time in Congress, which began in 2009.

Court records indicate Chapman's firm was drawing regulatory scrutiny as early as 2007.

Grayson also expressed concern that his identity as a victim was not protected by the court file, and that a defense motion and an attachment to a prosecution motion both identified him by name despite procedures that are supposed to be in place to protect victims' privacy.

"I think that's unfortunate," Grayson said. "They should have been more careful, should have used my initials throughout rather than using my name."

Before he was elected to Congress, Grayson practiced law and was best known for winning a major whistleblower lawsuit exposing fraud on a government contract in Iraq.

In the House, he is known as one the most sharp-tongued critics of Republicans, once famously summarizing Republican's health care plans as little more than wanting sick people to "die quickly."

The Associated Press contributed to this report