It was the high-tech key to a massive, illegal gambling kingdom: a laptop computer that authorities say was owned by a professional poker player named James Giordano.

Giordano, who rarely let the computer out of his sight, unknowingly gambled earlier this year by leaving it in his hotel room while attending a wedding on Long Island, police said Wednesday.

In the three hours he and his wife were away, New York Police Department investigators armed with a search warrant and computer expertise sneaked into the room, found the laptop on a desk and made a digital copy of the hard drive.

The covert operation on June 15 helped unlock a sophisticated billion-dollar-a-year gambling scheme that rivaled casino sports betting, authorities said at a news conference announcing charges against Giordano and 26 other defendants. It was the first such case since President Bush signed a ban on Internet gambling last month.

Giordano, 52, was arrested early Wednesday by FBI agents who had to scale the walls of his fortess-like Florida compound. Investigators also arrested Frank Falzarano, a former scout for the Washington Nationals, at his Long Island home.

"This is the largest illegal gambling operation we have ever encountered," said Police Commissioner Raymond Kelly.

Falzarano, 52, allegedly was a top earner in a network of 2,000 bookies who had taken more than $3.3 billion in cash wagers since 2004 from tens of thousands of customers nationwide.

Though the gambling ring relied on a Web site, it was different from the online betting operations targeted by recent federal legislation, said Deputy Inspector Brian O'Neill, who supervised the investigation.

The scheme involved placing sports bets through bookies, who would assign bettors a secret code to track their wagers and results through a restricted Web site, he said.

The defendants laundered and stashed away "untold millions of dollars" using shell corporations and bank accounts in Central America, the Caribbean, Switzerland, Hong Kong and elsewhere, said Queens District Attorney Richard Brown.

A total of 27 people in New York, New Jersey, Florida and Nevada were charged with enterprise corruption, money laundering, promoting gambling and other crimes.

Giordano was expected to be arraigned next week; prosecutors did not have the name of his lawyer.

Falzarano, who was ordered held on $500,000 bail after pleading not guilty, "looks forward to defending himself in court," said defense attorney Peter Tomao.

In a statement, the Nationals described Falzarano as a part-time scout whose contract expired on Oct. 31 and was not renewed. The team declined further comment.

Search warrants executed in several locations resulted in the seizure of gambling records, computers and hundreds of millions of dollars in property.

The seized property includes four Manhattan condominiums, millions of dollars in cash, tens of thousands of dollars worth of casino chips from the Bellagio casino in Las Vegas, jewelry, gold coins, and a football signed by the 1969 New York Jets following their Super Bowl victory. Also seized was original artwork by Peter Max and Salvador Dali.

Police launched the investigation last year after receiving a tip from a suspect in a separate organized crime probe.