"There can only be two possible situations," he said; "either this was a motiveless murder--and lack of motive means insanity; or else there was a deep reason for it and Redmayne killed Pendean, after plotting far in advance to do so and get clear himself. In the first case he would have been found, unless he had committed suicide in some such cunning fashion that we can't discover the body. In the second case, he's a very cute bird indeed and the ride to Paignton and disposal of the corpse--that all looked so mad--was super-craft on his part. But, if alive, mad or sane, I'm of opinion he did what he said in his letter to his brother he meant to do, and got off for a French or Spanish port. So that's the next step for me--to try and hunt down the boat that took him." He pursued this policy, left Princetown for Plymouth on the following day, took a room at a sailors' inn on the Barbican and with the help of the harbour authority followed the voyages of a dozen small vessels which had been berthing at Plymouth during the critical days. A month of arduous work he devoted to this stage of the inquiry, and his investigation produced nothing whatever. Not a skipper of any vessel involved could furnish the least information and no man resembling Robert Redmayne had been seen by the harbour police, or any independent person at Plymouth, despite sharp watchfulness. A time came when the detective was recalled to London and heartily chaffed for his failure; but his own unusual disappointment disarmed the amusement at his expense. The case had presented such few apparent difficulties that Brendon's complete unsuccess astonished his chief. He was content, however, to believe Mark's own conviction: that Robert Redmayne had never left England but destroyed himself--probably soon after the dispatch of his letter to Bendigo from Plymouth. Much demanded attention and Brendon was soon devoting himself to a diamond robbery in the Midlands. Months passed, the body of Michael Pendean had not been recovered, and the little world of Scotland Yard pigeon-holed the mystery, while the larger world forgot all about it.