Craig took the shell which O’Connor drew from another pocket and trying to fit the bullet and the cartridge together remarked “both from a .44, probably one of those old-fashioned, long-barrelled makes.”

“There,” concluded O’Connor ruefully, “you know all we know of the thing so far.”

“I may keep these for the present?” inquired Kennedy, preparing to pocket the shell and the bullet, and from his very manner I could see that as a matter of fact he already knew a great deal more about the case than the police.  “Take us down to this old house and dock, if you please.”

Over and over, Craig paced up and down the dilapidated dock, his keen eyes fastened to the ground, seeking some clue, anything that would point to the marauders.  Real persons they certainly were, and not any ghostly crew of the bygone days of harbour pirates, for there was every evidence of some one who had gone up and down the walk recently, not once but many times.

Suddenly Kennedy stumbled over what looked like a sardine tin can, except that it had no label or trace of one.  It was lying in the thick long matted grass by the side of the walk as if it had tumbled there and had been left unnoticed.

Yet there was nothing so very remarkable about it in itself.  Tin cans were lying all about, those marks of decadent civilisation.  But to Craig it had instantly presented an idea.  It was a new can.  The others were rusted.

He had pried off the lid and inside was a blackish, viscous mass.

“Smoking opium,” Craig said at last.

We retraced our steps pondering on the significance of the discovery.

O’Connor had had men out endeavouring all day to get a clue to the motor car that had been mentioned in some of the accounts given by the natives.  So far the best he had been able to find was a report of a large red touring car which crossed from New York on a late ferry.  In it were a man and a girl as well as a chauffeur who wore goggles and a cap pulled down over his head so that he was practically unrecognisable.  The girl might have been Miss Curtis and, as for the man, it might have been Clendenin.  No one had bothered much with them; no one had taken their number; no one had paid any attention where they went after the ferry landed.  In fact, there would have been no significance to the report if it had not been learned that early in the morning on the first ferry from the lower end of the island to New Jersey a large red touring car answering about the same description had crossed, with a single man and driver but no woman.

“I should like to watch here with you to-night, O’Connor,” said Craig as we parted.  “Meet us here.  In the meantime I shall call on Jameson with his well-known newspaper connections in the white light district,” here he gave me a half facetious wink, “to see what he can do toward getting me admitted to this gilded palace of dope up there on Forty-fourth Street.”