Devil's foot

Stories from the author's list of "12 favorite stories about Sherlock Holmes". Holmes and Watson go on vacation to Cornwall. A few days later, they were visited by Mr. Mortimer Tregenis and Mr. Rindhey, who reported that Mr. Tregenis' two brothers had gone mad and that their sister had died. Brenda died with a horrible look on her face. After some time, Mr. Mortimer Tregenis himself died, as di...