The investigation of these robberies was finally entrusted to me, and I suppose the empty room in Chelsea had never been used more often and with less result than over the Grange Park burglaries. It was not only one chance we had had of getting at the truth, for half a dozen houses had been broken into; and it was not the lack of clues which bothered us so much as the number of them. The thieves seemed to have scattered clues in every direction, yet not one of them led to any definite result. Like the rest of us, Christopher Quarles had his weaknesses. Whenever he failed to elucidate a mystery he was always able to show that the fault was not his, but somebody else's; either too long a time had elapsed before he was consulted, or some meddlesome fool had touched things and confused the evidence, or even that something supernatural had been at work. Once, at least, according to the professor, I had played the part of meddlesome fool, and one of my weaknesses being a short temper, it had required all Zena's tact to keep us from quarreling on that occasion. It came almost as a shock, therefore, when, after a long discussion one evening, he suddenly jumped up and exclaimed: "I'm beaten, Wigan, utterly beaten," and did not proceed to lay the responsibility for his failure on any one. Upon the receipt of Constable Poulton's message, I was sent for at once, and it was still early morning when I roused Quarles and we went to Grange Park. I do not think I have ever seen the professor so excited. Mrs. Crosland had a son and daughter and a nephew living with her. It was the daughter who had run down the drive and called Poulton. There were four servants, a butler and two women in the house and a chauffeur who lived over the garage. There was besides a nurse, for Mrs. Crosland was an invalid, often confined to her bed and even at her best only able to get about with difficulty. She suffered from some acute form of rheumatism and was tied to her bed at this time. The son's version of the tragedy was simple and straightforward. Hearing a noise, he had taken his revolver--always kept handy since the burglaries--and had reached the top of the stairs when his sister Helen came out of her room. She had also heard some one moving. They went down together to the landing at the angle of the staircase. He did not see any one in the hall, nor was there any sound just then. He called out "Who's there?" The answer was a bullet, which struck the wall behind them. Then Crosland fired down into the hall, but at random. He saw no one, but as a fact he shot the man through the head. "Do you think the man was alone?" I asked.