Island of Monsters by Jehoshaphat Shalom

Children's Literature: pirates mysteries, detectives, action and adventure.

An island where shape-shifting wraiths terrorize and sea monsters prowl in abandoned caverns--- Fawkes, Suzana, and Chaz are faced with new perils when they are hired to investigate an abandoned isle. Quickly, the mysteries multiply as they discover the hidden base of a missing scientist, but his science has been turned upside down. All paths suggest that dark things await at the island's center. But will the threat of the monsters that lurk in their midst prove to be too great? And will their investigation leave them trapped on the island forever . . ?

http://amzn.to/2xXrm1S