"He was a detective," said Raxel. "This is his house. I may as well put my cards on the table, I am a criminal, and I had need of your services. The detective you killed was on my trail, and it was necessary to remove him. I killed two birds with one stone. We captured him in the North, and brought him back here to his own house in London, a prisoner. His housekeeper's absence had already been assured by a fake telegram summoning her to the deathbed of her mother in Manchester. I then brought you here, drugged you with bhang, and gave you an automatic pistol."

She was aghast at a sudden recollection.

"I heard a shot--just as everything went blank. ..."

"You fired it," said Raxel smoothly, "but you are unlikely to remember that part."

Betty Tregarth caught her breath.

"It's impossible!" she cried hysterically. "I couldn't--"

Raxel sighed.

"You will disappoint me if you fail to behave rationally," he said, "The ordinary girl might be pardoned for such an outburst; but you, with your scientific training, should not need me, a layman, to explain to you the curious effects that bhang has upon those who take it. A blind madness seizes them. They kill, not knowing whom they kill, or why. That is what you did. Your first shot was successful. Naturally, you fired first at the unfortunate Inspector Henley, because I had so arranged the scene that he was the first man you saw at the instant when the drug took effect. I might mention that we had some difficulty in overpowering you afterwards and taking the pistol away from you. Henley died an hour later."

It was true--what Raxel had said was an absolute scientific fact. Granted that she had been drugged as he said, she would easily have been capable of doing what he said she had done.

"The terrifying circumstances," Raxel went on unemotionally, "probably hastened your intoxication. Your immediate impulse was to escape from the room at all costs, and Henley was the one man who stood between you and the door. You shot your way out--or tried to. It is all quite understandable.