“The writing was really his?”

“I’ve compared it with another letter in Bendigo Redmayne’s possession.  It’s a peculiar fist.  I should say there couldn’t be a shadow of doubt.”

“What shall you do next?”

“Get back to Plymouth again and make close inquiries among the onion boats.  They go and come and I can trace the craft that left Plymouth during the days that immediately followed the posting of Redmayne’s letter.  These will probably be back again with another load in a week or two.  One ought to be able to check them.”

“A wild-goose chase, Brendon.”

“Looks to me as though the whole inquiry had been pretty much so from the first.  We’ve missed the key somewhere.  How the man that left Paignton in knickerbockers, and a big check suit and a red waistcoat on the morning after the murder got away with it and never challenged a single eye on rail or road—­well, it’s such a flat contradiction to reason and experience that I can’t easily believe the face value.”

“No—­there’s a breakdown somewhere—­that’s what I’m telling you; but whether the fault is ours, or a trick has been played to put us fairly out of the running, no doubt you’ll find out soon or late.  I don’t see there’s anything more we can do up here whether or no.”

“There isn’t,” admitted Mark.  “It’s all been routine work and a devil of lot of time wasted in my opinion.  Between ourselves, I’m rather ashamed of myself, Halfyard.  I’ve missed something—­the thing that most mattered.  There’s a signpost sticking up somewhere that I never saw.”

The inspector nodded.

“It happens so sometimes—­cruel vexing—­and then people laugh at us and ask how we earn our money.  Now and again, as you say, there’s a danger signal to a case so clear as the nose on a man’s face, and yet, owing to following some other clue, or sticking to a theory that we feel can and must be the only right one, we miss the real, vital point till we go and bark our shins on it.  And then, perhaps, it’s too late and we look silly.”

Brendon admitted the truth of this experience.

“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.