John P. O'Neill was a former assistant director of the FBI who assisted in the capture of 1993 World Trade Center bomber Ramzi Yousef and was the head of security at the World Trade Center when he was killed trying to rescue people from the North Tower. Cantor Fitzgerald L.P., an investment bank on the 101st–105th floors of One World Trade Center, lost 658 employees, considerably more than any other employer. Marsh Inc., located immediately below Cantor Fitzgerald on floors 93–100 (the location of Flight 11's impact), lost 295 employees and 63 consultants. Risk Waters, a business organization, was holding a conference in Windows on the World at the time, with 81 people in attendance.