Walter Walsh, a former FBI agent and Marine who was the world’s oldest Olympian, died Tuesday, just six days shy of his 107th birthday. USA Shooting announced Walsh’s death Wednesday afternoon on Twitter. He competed for the United States in the 1948 London Games, placing 12th in the 50m free pistol event. But that achievement (at age 41) was a mere footnote in a memorable life. Walsh first gained fame as an FBI agent in the nascent days of the Bureau, discovering the body of noted gangster Baby Face Nelson after a shootout.