The Mystery of the Headless Horse — William Arden

Ruin threatens the proud old Alvaro family! They can't pay the mortgage on their ranch. Their house and barn have been destroyed in a suspicious fire. Their only hope is to find the family's priceless heirloom -- a jeweled sword that mysteriously disappeared over 100 years ago. Generations of Alvaros have failed to find it. Can the Three Investigators do any better?

The boys' task seems impossible -- until a statue of a headless horse yields an amazing clue!