Hector Xavier Monsagur is the lynchpin of the FBI's case against the other five, as Mr. Monsagur turned informant after the FBI identified him as "Sabu," the purported leader of LulzSec. Monsagur, a 28-year-old, unemployed single father of two from New York, is a "brilliant, but lazy" self-taught hacker who was identified after just once forgetting to cover his online tracks, one law enforcement official told Fox News.
Once the FBI knew that Monsagur was Sabu, they were able to keep tabs on him and eventually arrested him in June 2011 on identity theft charges. Monsegur cut a deal with the feds and pleaded guilty in August 2011 to stay out of prison and take care of his children. In return, he helped the FBI track down his comrades.
Wired notes that Sabu's disappearance around the time of his arrests prompted concerns among the Anonymous community that he had turned state's evidence. But according to Brian Knappenberger, who is editing a documentary on Anonymous, "whenever anyone [accused him of flipping] on Twitter, Sabu would respond with string of obscenities.”