Arden, William

When three junior detectives search for a valuable old Spanish sword lost since the Mexican War, the headless statue of a horse yields a clue.

While attending a week-long family reunion on a California island, the Three Investigators find their photographs of the event hold an inordinate interest for someone else, and receive clues to that unknown identity from both an ancient and a modern boating accident.

Three young sleuths uncover a mystery buried since World War II when they come to the aid of trouble-plagued environmentalist who is protesting the drilling of off-shore oil wells.

Three young detectives try to trap an invisible vandal who has been breaking car windows all over town.