As a con artist and swindler, Kevin Waltzer had genuine talent. He began by scamming $300,000 in a 1999 stock fraud, later displayed a knack for getting victims to invest in worthless companies, and ultimately orchestrated a complex, years-long fraud that stole $44.6 million.

But dozens of people were surprised when they discovered that Waltzer was proficient at a second skill, too.

Government informant.

The astonishment started with his wife, former NBC10 news anchor and reporter Lisa Mishler, with whom he owned a $1.5 million, elaborately landscaped Bucks County mansion. In 2007, Waltzer told her that his money came not from venture capitalism or day-trading in the stock market, but by stealing on a massive scale.

Her surprise was soon shared by the 19 people who have since been charged, and who have mostly pleaded guilty, as a result of Waltzer's active life as an undercover "cooperator."

Facing up to 30 years in prison, Waltzer, 42, spent $1 million on a bevy of defense lawyers. In 2007, as the IRS and FBI closed in, the attorneys developed an exit strategy that entailed Waltzer's confessing everything, and then wearing a wire for what he described as "thousands" of conversations with stock manipulators.

Testifying last month as the key government witness in a $26 million stock fraud - unrelated to that $44.6 million theft - Waltzer said he had been "providing information" on 50 to 100 people in hopes of getting a lighter sentence.

"I wanted to be the best possible cooperator I could," Waltzer said. His testimony helped convict a Toronto man, George Georgiou, who before becoming a Waltzer victim was his partner in financial fraud.

Waltzer's cooperation earned him a break, of sorts, last week.

He was sentenced to 11 years, rather than three decades, for being both an "extraordinarily prolific criminal" and an "extraordinary" informant, said Assistant U.S. Attorney Louis D. Lappen.

Even U.S. District Judge Stewart Dalzell agreed. A veteran of 20 years on the bench, Dalzell said he knew of no other white-collar informant who had been so effective on both sides of the law.

Unprecedented was one adjective Dalzell used.

More prosecutions based on Waltzer's tips are coming. Nevertheless, Dalzell brushed aside tearful pleas for a shorter sentence from Waltzer's wife, who said they had been the subject of death threats, and family members.

Dalzell was also unmoved by Waltzer's own plea that if given a brief sentence, "I'll go back to [stock] trading. I can make millions to pay them back."

The judge exceeded by 12 months the government's recommendation of 10 years, and told the 6-foot Waltzer - wearing a dark suit and light blue tie, his dark hair gone mostly gray - that any pain inflicted on his wife, three children, or extended family was solely "because of you."

Waltzer grew up in Rockland County outside New York City and attended Boston University. After graduating in 1990, he started day-trading stocks and investing in businesses. Eventually, he owned stakes in companies that included Headliners Entertainment, the New Jersey-based chain of comedy clubs and restaurants that went bankrupt in 2003.

Its chairman, Eduardo Rodriguez, would later become one of the people Waltzer targeted for the FBI.

In that case, Rodriguez and six others were charged in 2008 with artificially inflating stock prices by carefully timing trades and news releases to make it appear there was a genuine market demand, thereby driving up the price. When the insiders sold, the stock prices typically crashed, causing other investors to lose money.

The charges garnered national attention because one of the stocks pumped up in value was National Lampoon Inc., which owns the rights to Animal House and the various National Lampoon Vacation films starring Chevy Chase.

Prosecutors Lappen and Derek A. Cohen said that while Waltzer did not personally participate in that fraud, he had engaged in "numerous" other "pump-and-dump" schemes.

By all accounts Waltzer is personable, charming, always enthusiastic, and totally believable.

That's what landscaper Steven Wesler thought.

He is the owner of Northampton Gardens, and did the elaborate landscaping to Waltzer's home in Newtown.

"I considered him a friend, the son of a bitch," Wesler said.

In lieu of cash payments for his work, Waltzer persuaded Wesler to let him invest the funds. Wesler now has nothing to show for years of labor at Waltzer's home. Last year, he won a $338,669 judgment against Waltzer, but Mishler is challenging the award.

"I was at his son's bris," the landscaper said. "I'm still blown away. He completely scammed me."

Waltzer has been ordered to pay another business associate $407,249, and he owes PNC Bank $114,000.

No one has been paid, which on Friday raised another question.

"Where's the money?" the judge asked the prosecutors.

Lappen said the government seized $1.5 million of the $44.6 million stolen, and holds an unspecified amount of nonliquid assets, but the total unaccounted for is more than $30 million.

The rest has apparently been spent or lost in bad investments. A forensic investigation of Waltzer's records has failed to turn up more funds, Lappen said.

Waltzer was initially snared by the IRS, which was suspicious about a $3.5 million deposit he made in the Caribbean island of Nevis.

That money came from a big crime: the $44.6 million scam.

It involved Heffler, Radetich & Saitta L.L.P., a Center City accounting firm that specializes in distributing cash awards to plaintiffs in class-action lawsuits.

Between 2001 and 2007, Waltzer ran a system that filed fake multimillion-dollar claims after the settlement of major lawsuits against the Nasdaq stock exchange, Bank of America, and a business services firm, Cendant.

In each case, thousands of people were entitled to compensation ranging into the millions of dollars. Waltzer added himself to the list.

With varying degrees of help from five people he recruited, Waltzer set up fake corporations, forged fake brokerage paperwork, and created fake executive identities to justify his claims.

"It was as if he was printing money in his basement," Lappen said.

The stolen money should have been distributed among 200,000 plaintiffs in the three lawsuits. The amounts individual plaintiffs never received ranged up to $1.5 million, Lappen said.

To help him in the fraud, Waltzer recruited people far less financially sophisticated than himself.

Key to the scheme was Christian Penta, of Southampton, Burlington County, who had been making $40,000 a year at Heffler before being tutored by Waltzer and becoming his inside man in 2002. His share of the thefts was $4.3 million.

When Penta faced a $350,000 tax bill from the IRS, Waltzer paid it with his American Express card.

"Nice touch. That's what I call a Platinum card," Dalzell quipped.

In Florida, where Waltzer spent time and now lives with his family, he found a former Marine, Stephen Porto, to whom he paid $100,000 and dispatched on a three-day trip to Singapore to create a corporate front for a fake claim.

There was even Waltzer's friend since fifth grade, Paul Negroni of Mount Kisco, N.Y., who pleaded guilty to helping him. At one hearing, Negroni broke down and sobbed that if his buddy told him to jump off a bridge, "I probably would."

Waltzer is to report to prison on June 1.