The American Gun Mystery

In the arena of a vast New York sports palace, a man lay dead, murdered during the opening scene of a spectacular rodeo.
Can you, as Ellery Queen does, follow these clues to the murderer?
— A dead man's belt. What was the meaning of the deep ridges in the leather?
— An ivory handled revolver. How could the “feel” of the gun-butt provide a clue?
— The broken locks on a green box. Did the way the locks had been bent point the way to murder?
These are the big points in one of the toughest mysteries ever tackled by Ellery Queen. It was a murder witnessed by 20,000 people, but only Ellery solved it.
Do you think you can, too?