Former FBI counterterrorism expert John O'Neill retired from the bureau in 2001, became the head of security at the World Trade Center in August (8/11) 2001, and was killed there during the September 11 attacks.
He had led investigations into major al-Qaeda plots, including the 1993 World Trade Center bombing, the 1996 Khobar Towers bombing, and the 2000 USS Cole attack.
RIP, he chose the hill that he died on. And he was right.