“The only theory I can form is that the murders are the work of some irresponsible maniac,” said Mr. Ludgrove quietly.

“Would an irresponsible maniac have put a piece of poisoned glass on the end of Colburn’s pipe?” countered the Inspector quickly. “No, I am afraid that theory won’t do, Mr. Ludgrove.”

“I think it is the only theory which fits in with the assumption that these three men were all murdered by the same hand,” replied the herbalist.

“Yet I don’t think you can get away from that assumption,” said Inspector Whyland. “I don’t mind telling you something that worries me a bit, since it’s bound to come out at the inquest. One of the first things we found when we searched Pargent’s pockets in the mortuary was this.”