Black Hand Gang
The Black Hand Gang was a mafia group from Chicago with origins in Sicily, Italy. In 1911, they may have been responsible for a letter threatening to kidnap Louise Klehm's nieces if she did not hide $800 for them under a rock in St. Paul Park, owned by her father, George C. Klehm (now part of the Cook County Forest Preserve near the Morton Grove Train Station).
"Now you are a fool not to give us the money," one such missive, written in thick, black letters, began. "You do not seem to care about your life..." Such threats did not impress Dr. Klehm, though there was only a part-time policeman to protect her. Far more alarmed was her younger sister Alma, who appointed herself chief security guard, armed herself with a revolver, and took to accompanying the doctor on her rounds.