"What's that, my lord? What has the Frozen Flame to do with all this? Why, the answer to that is as simple as A.B.C. The Frozen Flames, or that most natural of phenomena, marsh-gas--of which I won't weary you with an explanation--arose from that part of the Fens where the rotting vegetation was at its worst. What more natural, then, than that this human fiend should endeavour to shape even this thing to his own ends? The villagers had always been superstitious of these lights, but their notice had never been particularly called to them before the story of the Frozen Flames had been carefully spread from mouth to mouth by Brellier's tools. "Then one man, braver than the rest, ventured forth--and never came back. The story gained credence, even with the more educated few. Another, unwilling to conform to public opinion, did likewise. And he, too, went into the great unknown. The list of Brellier's victims--supposed, of course, to be burnt up by the Frozen Flames--grew fairly lengthy in the four years that he has been using them as a screen for his underhanded work. A guard--and I've seen one of the men myself during a little midnight encounter that I had with him--went wandering over that part of the district armed with a revolver. The first sight of a stranger caused him to use his weapon. Meanwhile, behind the screen of the lights the bank robbers were bringing in their gold by motor and hiding the sacks down in a network of underground passageways that I also discovered--and traversed. They ran, by devious ways, both to a field in Saltfleet conveniently near the factory, and by another route up to the back kitchen of Merriton Towers. "You'll admit that, when I discovered this to be the case, I felt pretty uneasy about Sir Nigel's innocence. But a still further search brought to light another passage, which ran straight into the study of Withersby Hall, occupied by the Brelliers, and was hidden under the square rug in front of the fireplace. A nice convenient little spot for our friend here to carry on his good work. Just a few words to say that he didn't want to be disturbed in his study, a locked door, a rug moved, and--there you are! He was free from all prying eyes to investigate the way things were going, and to personally supervise the hiding of the gold. While outside upon the Fens men were being killed like rats, because one or two of them chose to use their intelligence, and wanted to find out what the flames really were. They found out all right, poor devils, and their widows waited for them in vain.