Updated

The imam who was a lightning rod during heated debate over a planned mosque near the World Trade Center terror site used millions of dollars in contributions to his separate charity for pricey vacations, a sports car and other personal expenses, a donor says in a lawsuit that comes after the imam accused the contributor of defrauding him.

The new suit, filed Monday in a Manhattan state court, deepens a financial feud between Imam Feisel Abdul Rauf and Robert Leslie Deak, a businessman who for a time backed Rauf in efforts to foster public understanding of Islam. Rauf has been pursuing his own claims against Deak in a federal court since 2011.

Rauf co-led efforts to build the lower Manhattan Islamic center for a time in 2010, when the proposal became a flashpoint for protests in the lead-up to the Sept. 11 terror attack anniversary that year. Rauf's role in the as-yet-unbuilt project was reduced in January 2011, and it's unclear what his role is now; a spokesman for the organizers didn't immediately return a call Tuesday evening.

The legal fight between Rauf and Deak concerns Rauf's own organizations, chiefly the Cordoba Initiative.

Deak, in the new suit, says Rauf bought himself real estate, took trips with a woman other than his wife and bought gifts with $167,000 that Deak provided for an education project intended to combat anti-Islamic sentiment.

The $20 million fraud suit says Rauf also misused $3 million the Malaysian government gave Cordoba. The Malaysian Embassy had no immediate comment Tuesday evening.

Deak and his wife, Moshira Solimon, "are shocked and disappointed that their generosity and philanthropy have been preyed upon by Rauf and that their gifts were used for his own personal enjoyment," said their lawyer, Jonathan B. Nelson.

"Information began to trickle in" about financial improprieties after the couple and Rauf began working closely on projects in 2010, Nelson said.

Rauf's lawyer, Paul L. Knight, said the imam and his groups deny the allegations.

"The lawsuit is meritless, and it will be vigorously defended," Knight said.

Rauf, in turn, says in his lawsuit that Deak and Solimon gained his trust during a more than five-year friendship, but then ripped him off in the 2010 purchase of a Washington apartment that was to be used as a base for Cordoba's activities in the capital.

The couple told him the condominium was worth more than $1.3 million when they had bought it months before for $567,000, the suit says. Not knowing that, he wired them $1.5 million to buy and furnish the apartment -- money they used to buy a different apartment, according to the $1.5 million suit, filed in federal court in Washington.

The couple has denied those claims.

Deak, who lives in Washington and Rye, New York, heads a firm that develops and manages companies in the United States and the Middle East.

His father, Nicholas Deak, headed a foreign exchange firm after what news outlets have chronicled as a colorful experience serving with the Office of Strategic Services, the U.S. intelligence agency during World War II. Time magazine once called him "the James Bond of the world of money."

The elder Deak and a receptionist were murdered by a mentally ill woman in their offices in 1985.