"They say he jumped, spun round, and fell across the pavement. And they all thought it was a case of suicide. That, of course, gave the murderer a bigger and better chance of making off. You see, as these people saw no assailant, it never struck 'em that the shot had been fired from behind this window. When they collected their thoughts, found it wasn't suicide, and realized that it was murder, the murderer was--Lord knows where! From behind these old houses, Mr. Allerdyke, there's a perfect rabbit-warren of alleys, courts, slums, twists, and turns! The man could slip out at the back, go left or right, mix himself up with the crowd on the quays and wharves, walk into the streets, go anywhere--all in a minute or two." "Clever--very clever! You've no clue?" asked Allerdyke. "None; not a scrap!" replied the detective. "Bless you, there's score of foreigners knocking about Hull. Scores! Hundreds! We've done all we can, the local police and myself--we've no clue whatever. But, of course, it was done by one of the gang." "By one of the gang!" exclaimed Allerdyke. "Ah you've got a theory of your own, then?" Chettle laughed quietly as they turned and retraced their steps up the street. "It 'ud be queer if I hadn't, by this time," he answered. "Oh yes, I've thought things out pretty well, and I should say our people at the Yard have come to the same conclusion that I have--I'm not conceited enough, Mr. Allerdyke, to fancy that I'm the only person who's arrived at a reasonable theory, not I?" "Well--what is your theory?" asked Allerdyke. "This," replied the detective. "The whole thing, the theft of the Princess Nastirsevitch's jewels from your cousin, of Miss de Longarde's or Lennard's jewels, was the work of a peculiarly clever gang--though it may be of an individual--who made use of both Lydenberg and the French maid as instruments, and subsequently murdered those two in order to silence them forever. I say it may be the work of an individual--it's quite possible that the man who killed the Frenchwoman is also the man who shot Lydenberg--but it may be the work of one, two, or three separate persons, acting in collusion. I believe that Lydenberg was the actual thief of the Princess's jewels from your cousin; that the Frenchwoman actually stole her mistress's jewels. But as to how it was worked--as to who invented and carried out the whole thing--ah!" "And to that--to the real secret of the whole matter--we haven't the ghost of a clue!" muttered Allerdyke. "That's about it, eh?" Chettle laughed--a sly, suggestive laugh. He gave his companion one of his half-apologetic looks. "I'm not so sure, Mr. Allerdyke," he said. "We may have--and that's why I wanted to see you by yourself. Come round to the police-station."