Erle Stanley Gardner 
D.A. Draws a Circle [EPUB ebook] 

The murdered man had been shot — twice. Either bullet could have caused the death.D.A. Doug Selby had both the bullets and one of the guns. On that gun were the fingerprints of Pete Ribber, a known criminal. The other bullet was from a different — and missing — gun.Which bullet had caused the death? That was the D.A.’s problem. Because there’s no law against firing a bullet into a corpse …