U.S. law enforcement scored a major victory against the international hacking group known as Anonymous on Monday after one of the members flipped on his brethren, leading to the arrests of five other suspects.

Court documents released on Monday tell the tale Hector Xavier Monsegur, also known as Sabu, who was one of the reported leaders of Anonymous and an off-shoot group LulzSec, which have claimed responsibility for a host of high-profile hacks against the likes of Sony, Fox, PBS and various government websites.

The 28-year-old Manhattan resident was arrested back in June of 2011, at which time he admitted to hacking into Sony Pictures Entertainment and Sony Music Entertainment, and then sharing the confidential data with members of LulzSec, according to Bloomberg. Monsegur quietly plead guilty to around a dozen hacking charges in August but continued working with Anonymous, reportedly as the eyes and ears of the FBI.

“If that’s true, he’s an absolute traitor,” Barrett Brown, an informal spokesman for Anonymous, told Bloomberg. “God knows what’s compromised.”

With Monsegur's help, the FBI has reportedly solved one of the more embarrassing hacks against law enforcement, when a 17-minute conference call between the FBI and Scotland Yard was illegally recorded and released on YouTube in February. The call covered on-going investigations related to Anonymous, Lulzsec, Antisec, and other associated splinter groups.

Donncha O'Cearrbhail, 19, of Birr, Ireland, was arrested on charges related to the hack with cooperation from Monsegur, referred to as "CW" in the indictment, who acted under the direction of the FBI to record Internet chat logs between himself and "anonsacco," who is believed to be O'Cearrbhail, according to the Guardian.

O'Cearrbhail contacted Monsegur on two occasions asking for help in recording the call. "Hey mate. Would you like a recording of a call between SOCA and the FBI regarding anonymous and lulzsec?" he said. "I think we need to hype it up. Let the feds think we have been recording their calls."

The Guardian reports that Monsegur received the file, which was then checked by the FBI and found to be genuine. The recording was posted on YouTube five days later. It is believed that Monsegur eventually helped the FBI discover the identity of O'Cearrbhail through other online conversations that revealed his Internet address and services that he used, according to the Guardian.

O'Cearrbhail is charged with one count of computer hacking conspiracy and one count of intentionally disclosing an unlawfully intercepted wire communication, and faces a maximum 15 years in prison if convicted of both charges.

The FBI also nabbed four other suspects with ties to Anonymous or Antisec – Ryan Ackroyd, Jake Davis, Darren Martyn and Jeremy Hammond – who were said to have “waged a deliberate campaign of online destruction, intimidation and criminality” Manhattan U.S. Attorney Preet Bharara noted in a statement.

It is unclear if Monsegur had any hand in the arrests of the four other suspects.