Federal Bureau of Investigation

Founded in 1908 and headquartered at the J. Edgar Hoover Building in Washington, D.C., the FBI doubles as the nation's lead federal law-enforcement arm and its domestic intelligence service. Across the series its agents recur in shifting roles, but the bureau's defining contribution is the squad of operatives it commits to hunting Kira, an effort that proves disastrous for the people it sends.

Early in the hunt, twelve agents are dispatched to Japan to quietly probe police personnel and their relatives. One of them, Raye Penber, shadows Light Yagami, the investigation's leading suspect. Light maneuvers Penber into flashing his identification, learns his name, then phones him claiming to be Kira and proves it with a killing. Under threat, Penber boards a train, collects a prepared envelope, and unwittingly transcribes every agent's name onto a sheet torn from a notebook, wiping out all twelve. With his task force gutted, bureau director Steve Mason severs the agency's partnership with L and withdraws.

Years later Mason revives the effort, joining Near to stand up the Special Provision for Kira, an organization drawn largely from FBI ranks. That body suffers its own massacre when the Mafia, acting on Mello's command, writes most of its members to death. Across other versions the bureau's beats recur with fresh faces. The first live-action film recasts Penber as Raye Iwamatsu, while L: Change the WorLd introduces agent Hideaki Suruga, who pursues L's notebook before switching to his side. The stage musical, the 2015 television drama with its agent Mark Dwellton, and the Netflix adaptation each restage the twelve-agent slaughter with their own rosters and methods of death.

Raye Penber draws the assignment to watch the Yagami and Kitamura households and becomes the instrument of his colleagues' deaths once Light uncovers his name. Steve Mason, the director, brings the original twelve to Japan, pulls support after they perish, then later helps Near build the SPK and dies in its slaughter. Naomi Misora, a former agent who had worked beside L during the Los Angeles serial murders, left the bureau to marry Penber; after his death she seeks out L, crosses paths with Light at the police station, and is manipulated into revealing her name and a written suicide, her body never found. John McEnroe, attached to the SPK, presses the National Police Agency to surrender the captured notebook, is wrongly accused of abducting director Kanichi Takimura, clears himself, aids in freeing Sayu Yagami, and is presumed among the SPK members the Mafia kills.