Law enforcement agencies in the U.K. and the United States arrested five leading members of the hacking group LulzSec Tuesday morning after a months-long investigation.

Jana Winter at Fox News reports the arrests were made possible after turning the senior leader, Hector Xavier Monsegur, last June.

With Monsegur's help, agents arrested two men from Great Britain, two from Ireland, and an American in Chicago.

“This is devastating to the organization,” an FBI official told Fox. “We’re chopping off the head of LulzSec.”

LulzSec is a loose branch of the larger hacking group known as Anonymous, that officials claim have caused billions of dollars in damage to banks, corporations, and governments.

Monsegur is an unemployed 28-year-old father of two, who had allegedly been operating out of a housing project in New York's Lower East Side when he was arrested and began working for the FBI last summer.

It is Monsegur who named "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 is the man believed to be responsible for the Stratfor attack last December.

Read Winter's full exclusive at Fox >