Steve Mason is the FBI Director who authorizes the secret probe into the Japanese police at L’s request — and the man whose decision to pull out after Kira kills twelve of his agents forces L to reveal himself to the Task Force for the first time. His withdrawal is the domino that changes the entire shape of the early investigation.
Professional and decisive, with a pragmatic sense of loyalty rather than blind deference. Mason respects L’s intellect enough to greenlight an illegal international operation on his word alone, but he isn’t a rubber stamp — once the human cost becomes real, his duty to his own agents outweighs his commitment to L’s investigation.
In December 2003, L asks Mason to secretly deploy agents to Japan to tail 141 NPA members and their families, including the Yagamis. Mason authorizes twelve agents for the mission and personally hands L the full watch list. Unknown to him, Light Yagami identifies and kills all twelve, including Raye Penber, on December 27. Citing the “twelve precious lives” lost, Mason pulls the FBI out of the investigation entirely in January 2004 — a withdrawal that costs L the Japanese Task Force’s trust and forces him to meet the remaining investigators face-to-face to keep the case alive.
The Loss of Twelve Agents (Ch. 10–11)
Kira wipes out Mason’s entire Japan-based team in a single stroke. Mason withdraws all FBI support in response — Kira’s first major tactical win against L’s international resources, forcing L to expose himself to keep the investigation from collapsing.
Minor: Ch. 5, 11.
Mentioned only: Ch. 10, 14, 21.
L (Ryuzaki)
A professional associate built on mutual respect, until Mason judges L’s methods too costly to continue backing.
Raye Penber
His subordinate, and the most prominent agent lost in the Japan mission.
Watari
The liaison Mason coordinates through to receive L’s requests.
“The clue I’ve managed to get was obtained by sacrificing the lives of 12 FBI agents. Twelve precious lives…” — Chapter 11, reported by L as Mason’s reason for withdrawing
- Indirectly responsible for L revealing his face to the Task Force — without the FBI’s withdrawal, L might have kept investigating from the shadows indefinitely.
- By authorizing surveillance of NPA personnel and their families, he technically authorized a violation of Japanese sovereignty.
🇯🇵 Japanese Voice Actors
Ogata, Mitsuru
🇯🇵 Japanese
🇺🇸 English Voice Actors
Novak, John
🇺🇸 English