The Hound of the Baskervilles1939

Sherlock Holmes:
The person who wanted to snuff out your life, Sir Henry, was the same one who plotted to kill your uncle. He wanted to get you both out of the way so that he could lay claim to this place, to the whole Baskerville estate. In tracing back his lineage, he discovered not only that he was the next of kin, but also learned that old legend about the hound. So he brought the hound to life by the simple expedient of buying the most savage dog that he could find and hiding it here on the moor until he needed it. If he had succeeded tonight, the blame would have fallen on the legendary monster, and no possible suspicion would have been attached to him. A most ingenious device. And I'm quite sure that he would have had no difficulty in proving his claim to Baskerville Hall and all that goes with it.