A circus-performer-turned-PI deals with sinister sleight of hand in a novel that "gleefully subvert[s] most of the rules of mystery fiction" (Publishers Weekly).   With a genius IQ, a past career as a circus acrobat, and a black belt in karate, criminology professor Dr. Robert Frederickson--better known as "Mongo the Magnificent"--has a decidedly unusual background for a private investigator. He also just so happens to be a dwarf.   Mongo and his brother, Garth, are experienced private detectives. So when Garth's wife Mary's strange ex-boyfriend shows up uninvited, they suspect he, the self-proclaimed magician Sacra Silver, is full of mumbo jumbo. But when a series of annoying pranks disrupts their lives, Mongo and Garth have to deal with Sacra's attempts at black magic.   Meanwhile, they're also investigating a death involving a suspicious multinational corporation. Garth's friend, environmental cop Tom Blaine, was found in the Hudson chopped to pieces by a boat propeller--just like the kind on the tanker the victim had seen dumping oil in the river . . .   The two problems couldn't be less alike, but soon Mongo learns the dirty dealings have a connection that could put everyone he loves in danger.   An Incident at Bloodtide is the 12th book in the Mongo Mysteries, but you may enjoy reading the series in any order.