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EXCLUSIVE: Law enforcement agents on two continents swooped in on top members of the infamous computer hacking group LulzSec early this morning, and acting largely on evidence gathered by the organization’s brazen leader -- who sources say has been secretly working for the government for months -- arrested three and charged two more with conspiracy.

Charges against four of the five were based on a conspiracy case filed in New York federal court, FoxNews.com has learned. An indictment charging the suspects, who include two men from Great Britain, two from Ireland and an American in Chicago, is expected to be unsealed Tuesday morning in the Southern District of New York.

“This is devastating to the organization,” said an FBI official involved with the investigation. “We’re chopping off the head of LulzSec.”

The offshoot of the loose network of hackers, Anonymous, believed to have caused billions of dollars in damage to governments, international banks and corporations, was allegedly led by a shadowy figure FoxNews.com has identified as Hector Xavier Monsegur. Working under the Internet alias “Sabu,” the unemployed, 28-year-old father of two allegedly commanded a loosely organized, international team of perhaps thousands of hackers from his nerve center in a public housing project on New York’s Lower East Side. After the FBI unmasked Monsegur last June, he became a cooperating witness, sources told FoxNews.com.

“They caught him and he was secretly arrested and now works for the FBI,” a source close to Sabu told FoxNews.com.

Monsegur pleaded guilty Aug. 15 to 12 hacking-related charges and information documenting his admissions was unsealed in Southern District Court on Tuesday.

As a result of Monsegur’s cooperation, which was confirmed by numerous senior-level officials, the remaining top-ranking members of LulzSec were arrested or hit with additional charges Tuesday morning. The five charged in the LulzSec conspiracy indictment expected to be unsealed were identified by sources as: Ryan Ackroyd, aka “Kayla” and Jake Davis, aka “Topiary,” both of London; Darren Martyn, aka “pwnsauce” and Donncha O’Cearrbhail, aka “palladium,” both of Ireland; and Jeremy Hammond aka “Anarchaos,” of Chicago.

Hammond was arrested on access device fraud and hacking charges and is believed to have been the main person behind the devastating December hack on Stratfor, a private company that provides geopolitical analysis to governments and others. Millions of emails were stolen and then published on Wikileaks; credit card numbers and other confidential information were also stolen, law enforcement sources told FoxNews.com.

This is devastating to the organization. — Senior FBI official

The sources said Hammond will be charged in a separate indictment, and they described him as a member of Anonymous.

The others are all suspected members of LulzSec, the group that has wreaked havoc on U.S. and foreign government agencies, including the CIA and FBI, numerous defense contractors, financial and governmental entities and corporations including Fox and Sony.

Ackroyd, who is suspected of using the online handle “Kayla,” is alleged to be Monsegur’s top deputy. Among other things, Kayla identified vulnerabilities in the U.S. Senate’s computer systems and passed the information on to Sabu. Kayla was expected to be taken into custody on Tuesday.

A spokeswoman for the Southern District and U.S. Attorney Preet Bharara declined comment.

Monsegur’s attorney did not return FoxNews.com’s repeated requests for comment.