At the large public housing project in New York City where he lived, outsiders knew him as a quiet family man. But federal prosecutors say Hector Xavier Monsegur was an Internet saboteur known as Sabu.

During the Arab spring, prosecutors say he hacked into government Web sites in Tunisia, Yemen and Algeria. He helped coordinate attacks on credit card companies after they refused to accept donations to Wikileaks. Then, they said, he added another layer to the subterfuge by informing on his accomplices after he was caught by the FBI last spring.