“Well, now that things have come to this pass,” he said, “and after Sir Gilbert’s deliberate attempt to get rid of Moneylaws—­to murder him, in fact—­I don’t mind telling you the truth.  I do suspect Sir Gilbert of the murder of Crone—­and that’s why I produced that ice-ax in court the other day.  And—­when he saw that ice-ax, he knew that I suspected him, and that’s why he took Moneylaws out with him, intending to rid himself of a man that could give evidence against him.  If I’d known that Moneylaws was going with him, I’d have likely charged Sir Gilbert there and then!—­anyway, I wouldn’t have let Moneylaws go.”

“Aye!—­you know something, then?” exclaimed Murray.  “You’re in possession of some evidence that we know nothing about?”

“I know this—­and I’ll make you a present of it, now,” answered Mr. Lindsey.  “As you’re aware, I’m a bit of a mountaineer—­you know that I’ve spent a good many of my holidays in Switzerland, climbing.  Consequently, I know what alpenstocks and ice-axes are.  And when I came to reflect on the circumstances of Crone’s murder, I remember that not so long since, happening to be out along the riverside, I chanced across Sir Gilbert Carstairs using a very late type of ice-ax as a walking-stick—­as he well could do, and might have picked up in his hall as some men’ll pick up a golf-stick to go walking with, and I’ve done that myself, hundred of times.  And I knew that I had an ice-ax of that very pattern at home—­and so I just shoved it under the doctor’s nose in court, and asked him if that hole in Crone’s head couldn’t have been made by the spike of it.  Why?  Because I knew that Carstairs would be present in court, and I wanted to see if he would catch what I was after!”

“And—­you think he did?” asked the superintendent, eagerly.

“I kept the corner of an eye on him,” answered Mr. Lindsey, knowingly.  “He saw what I was after!  He’s a clever fellow, that—­but he took the mask off his face for the thousandth part of a second.  I saw!”

The two listeners were so amazed by this that they sat in silence for a while, staring at Mr. Lindsey with open-mouthed amazement.

“It’s a dark, dark business!” sighed Murray at last.  “What’s the true meaning of it, do you think, Mr. Lindsey?”

“Some secret that’s being gradually got at,” replied Mr. Lindsey, promptly.  “That’s what it is.  And there’s nothing to do, just now, but wait until somebody comes from Holmshaw and Portlethorpe’s.  Holmshaw is an old man—­probably Portlethorpe himself will come along.  He may know something—­they’ve been family solicitors to the Carstairs lot for many a year.  But it’s my impression that Sir Gilbert Carstairs is away!—­and that his wife’s after him.  And if you want to be doing something, try to find out where she went on her bicycle yesterday—­likely, she rode to some station in the neighbourhood, and then took train.”

Mr. Lindsey and I then went to the office, and we had not been there long when a telegram arrived from Newcastle.  Mr. Portlethorpe himself was coming on to Berwick immediately.  And in the middle of the afternoon he arrived—­a middle-aged, somewhat nervous-mannered man, whom I had seen two or three times when we had business at the Assizes, and whom Mr. Lindsey evidently knew pretty well, judging by their familiar manner of greeting each other.