Joshua Schulte was once employed making cyberweapons for the CIA. Feeling wronged by the agency after a dispute with a colleague, he allegedly retaliated by releasing troves of secret data on WikiLeaks, exposing US hacking methods and assets. When the FBI investigated him, they discovered that Schulte had some deep dark secrets of his own.

On March 7, 2017, the Web site WikiLeaks launched a series of disclosures that were catastrophic for the C.I.A. As much as thirty-four terabytes of data—more than two billion pages’ worth—had been stolen from the agency. The trove, billed as Vault 7, represented the single largest leak of classified information in the agency’s history. Along with a subsequent installment known as Vault 8, it exposed the C.I.A.’s hacking methods, including the tools that had been developed in secret by the O.S.B., complete with some of the source code.