in 1868 cook tracked down the notorious musgrove-franklin gang, who were credited with twelve murders, and apprehended gang leader l. h. musgrove in the wyoming territory. having subsequently transported musgrove to jail in denver, cook cleverly predicted his partner ed franklin would attempt a rescue. upon franklin's arrival into denver, cook tracked him to a room in the overland hotel. franklin reportedly reached for a pistol and cook shot him to death.