French’s tone became a trifle sterner.

“I wonder if you quite understand the position. It has been established that some person or persons went to Starvel on the evening we are speaking of, murdered Mr. Averill and Roper and his wife,” Whymper gave an exclamation of dismay, “stole Mr. Averill’s fortune and then set fire to the house. So far as we know, you alone visited the house that night, some of the stolen money was found in your possession, and when I give you the chance of accounting for your actions, you don’t take it. Do you not understand, Mr. Whymper, that if you persist in this foolish attitude you will be charged with murder?”

Whymper’s face had become ghastly and an expression of absolute horror appeared on his features. For a moment he sat motionless, and then he looked French straight in the face.

“It’s not my secret. I can’t tell you,” he declared with a sudden show of energy and then sank back into what seemed the lethargy of despair.

French was more puzzled than ever. The facts looked as bad as possible, and yet if Whymper’s tale were true, he might be absolutely innocent. And French’s inclination was to believe the story so far as it went. The secret might be something discreditable affecting, not Mr. but Miss Averill, which would account for the man’s refusal to reveal it. On the other hand could Whymper be hiding information about the Starvel crime? Was he even shielding the murderer? Could he, learning what had occurred and finding proof of the murderer’s identity, have himself set fire to the house with the object of destroying the evidence? Somehow, French did not think he was himself the murderer, but if he knew the identity of the criminal he was an accessory after the fact and guilty to that extent.

Whether or not he should arrest the young man was to French a problem which grew in difficulty the longer he considered it. On the whole, he was against it. If Whymper turned out to be innocent such a step would, of course, be a serious blunder, but even if he were guilty there were objections to it. Arrest might prevent him from doing something by which he would give himself away or at least indicate the correct line of research. Free, but with arrest hanging over him, the man would in all probability attempt to communicate with his accomplice—if he had one—and so give a hint of the latter’s identity. French made up his mind.

“I have more than enough evidence to arrest you now,” he said gravely, “but I am anxious first to put your story to a further test. I will, therefore, for the present only put you under police supervision. If you can see your way to complete your statement, I may be able to withdraw the supervision. By the way, have you got the note Mr. Averill enclosed with the £500?”

“Yes, it is in my rooms.”

“Then come along to your rooms now and give it to me. You had better hand over the notes also, for which, of course, I’ll give you a receipt. I shall also want a photograph of yourself and a sample of your handwriting.”

When French reached the hotel he took out some samples of Mr. Averill’s handwriting which he had obtained from Mr. Tarkington and compared them with that of Whymper’s note. But he saw at a glance that there was nothing abnormal here. All were obviously by the same hand.