The dead man resists, upon which the other kills him by means of the chloroform which he had with him, and being afraid that the cab will stop, and he will be found out, snatches what he wants out of the pocket so quickly that he tears the waistcoat, and then makes off. That's clear enough, but the question is, What was it he wanted? A case with jewels? No! It could not have been anything so bulky, or the dead man would never have carried it about inside his waistcoat. It was something flat, which could easily lie in the pocket - a paper - some valuable paper which the assassin wanted, and for which he killed the other.