Dragon's Claw - Peter O'Donnell

On the island of Dragon's Claw, Sam Solon, an Australian newspaper
tycoon with an inferiority complex about his lack of knowledge of art,
has kidnapped the world's leading art experts, keeping them prisoner to
admire his collection of stolen art treasures. Modesty and her loyal
lieutenant, Willie Gavin, become involved in a complex series of murder
mysteries that takes them to the island as prisoners. To escape, they
must defeat Solon's hired killers: the Reverend Uriah Crisp, an ordained
minister with the greatest handgun shot in the world, and Beauregard
Browne, who kills his victims using the famous handkerchief trick.