On March 18, 1917, Officer Harry J. Keating - out of uniform - was waiting at the corner of 9th and Main Streets for a street car when he saw a man he wanted to arrest. Witnesses reported that he had the man on his knees at gunpoint, when William B. Leahy - a Pinkerton officer - saw him and thought Officer Keating was holding up the man. Leahy drew his gun and advanced, demanding that Officer Keating drop his weapon. Officer Keating turned to face Leahy, and Leahy - believing that he would be shot - fired on Keating. Officer Keating was mortally wounded and the prisoner escaped. Leahy was also out of uniform at the time, and the two men did not know each other.