So it happened that the doctor’s evidence at the inquest remain unchallenged. The theory was that Martin, having decided to take his own life, was attracted to his old premises knowing them to be empty. In order to obtain access, he telephoned himself from Aldersgate station to Mr. Briggs, using Mr. Lacey’s name. Having thus secured the key, he bolted the door behind him to prevent any interruption, then went into the cellar and inhaled the vapour of prussic acid. The automatic he had brought with him in the case the poison should prove ineffective. The numbered counter, which he had also brought with him, as the finger-marks upon it showed, merely emphasized the morbid state of mind which had prompted him to the deed.
The jury returned a verdict of suicide during temporary insanity, in accordance with this theory, and, to all outward appearances the case of Mr. Martin was disposed of. But Inspector Whyland, although relieved to feel that yet another unsolved crime had not been added to his already mounting debit account, knew well enough at heart that once again his mysterious adversary had scored a point against him. But again, there was this insoluble riddle of motive. It was possible to suggest more than one motive for the murder of Mr. Martin. He might, for instance, have fallen out with one of the jewel thieves with whom he had such intimate relations. Or again, his dealings with women might have been at the bottom of it. But, assuming one of these suppositions to be correct, how was the death of Mr. Martin to be linked with the previous murders? Or were they indeed all the work of separate persons, who imitated one another’s methods with a view to confusing the issue?
Inspector Whyland recalled his mind from such unprofitable speculations. He felt that the solution of the whole mystery lay close under his hand, if he could but devise the means to unearth it. Somehow Mr. Copperdock’s name always came up in connection with these murders. He had been Tovey’s most intimate friend. The pipe which had been the cause of Colburn’s death had been bought at his shop. He must have been within a few yards of the scene when Pargent was murdered. And Whyland had no doubt that he would discover some point of contact between Mr. Copperdock and the present case.
He was not disappointed. It came out, in the course of a conversation between him and Houlder, the builder. It seemed that Houlder, who was an occasional frequenter of the Cambridge Arms, had mentioned, early in the month, that a new tenant had taken Number 407, and that he had got the job of altering the premises for him. Mr. Copperdock had displayed great interest in this remark, and as a result Houlder had invited him to come and look over the place. Mr. Copperdock had accepted, and he and Houlder had been over every inch of it. This might have been pure curiosity on Mr. Copperdock’s part, but at least the fact was significant. Inspector Whyland stored it in the mental pigeon-hole which already contained the note that Martin and Copperdock had done considerable business together in the past.
Thus, putting the case mathematically, Mr. Copperdock was the highest common factor of the terms representing the four dead men. Inspector Whyland had spent much time and care in investigating their histories and their actions, and he could find no other factor common to them all. They had been, so far as he had been able to ascertain, complete strangers to one another, and they could never consciously have met one another. The only characteristics which they had in common were that they had all received counters numbered in the order of their deaths, that they were all males, and that their ages had all been over fifty.
Naturally, the mind of Praed Street was not greatly relieved by the verdict on the death of Mr. Martin. Violent death was becoming far too frequent an incident for any of the local community to feel safe. Men wondered when it would be their turn to find the fatal counter, and how they should ward off the death which so swiftly followed. It was not as though one could tell exactly what one had to guard against. The knife had been used twice, certainly, but poison in one form or another had accounted for two of the deaths.
The numbered counters were the characteristic feature of the case which appealed most strongly to the popular imagination. Inexplicable murders were common enough, even murders in which no motive or criminal had ever been found. But a series of murders, each prefixed by a definite warning, were an entirely novel sensation. The theory of the counters was publicly discussed from every possible point of view, without any really satisfactory theory being arrived at. Quite a large proportion of the population of London opened their morning papers in expectation of finding news of the delivery of counter number V.
The news, when it came, illustrated the hold which the subject had upon men’s minds, and the moral effect which it has produced. Mr. Ludgrove read the story as he consumed his frugal breakfast, and he was not surprised to hear Mr. Copperdock’s voice in the shop a few minutes later.
“Come in, Mr. Copperdock,” he called, and the tobacconist, paper in hand, the light of excitement in his eyes, entered through the curtained door.
“Have you seen this about this old chap Goodwin?” he enquired, without preliminary.