Devil's foot

Stories from the author's list "12 favorite stories about Sherlock Holmes". Holmes and Watson go on vacation to the county of Cornwall. A few days later, they are visited by Mr. Mortimer Tregenis and Mr. Rhyndhey, who report that two of Mr. Tregenis' brothers have gone mad and their sister has died. Brenda died with a horrible expression on her face. After some time Mr. Mortimer Tregenis himsel...