I explained how, recognizing the poison used, I had watched the house each night.
"Not every night," she laughed. "Three times at least you have missed, for we've been here on three occasions."
"What was the motive of getting rid of young Wray?" I asked.
"The same as the others. To close his lips. He was a clerk at a money-changer's in Moorgate Street, and he one day recognized Otto as a man who had exchanged at a bureau de change in Calais, two forged thousand-franc notes for English gold. Otto became friendly and Wray sought, of course, to learn more. He accepted an invitation to supper here, intending to give away his friend to the police next day. But—well, he did not live to do so, that's all!"
"Several persons have, I suppose, been assisted out of the world in a similar manner by Otto?" I remarked.
She nodded with an evil grin.
"Why do you fear his son? Surely he should fear you, Mrs. Netherall?"
"No. In this house, up in the attic, Heinrich Otto had seventy thousand pounds' worth of forged French notes concealed—notes which he printed before he gave up the work
