Lewis Robinson’s first book, published in 2003, was a critically acclaimed collection of short stories titled Officer Friendly. His new novel is called Water Dogs (Random House, New York, New York; hardcover; 239 pages; $25), but if Robinson had wanted to continue the law-enforcement motif he might also have gone with Arrested Development.

The main character of this stark and suspenseful tale is a twenty-seven-year-old college dropout named Bennie who works at an animal shelter and inhabits the rotting family home — appropriately nicknamed “the Manse” — on fictional Meadow Island with his mulish older brother, Littlefield. Bennie and his siblings are not technically orphans, but following the sudden death of their father and subsequent estrangement from their mother, they’ve watched their lives tumble off a cliff. The question of how to grow into healthy and happy adulthood has left Bennie confounded and Littlefield enigmatic.

Bad goes to worse one Saturday afternoon when Bennie and Littlefield decide to play paintball against a trio of macho urchin divers in the teeth of a blizzard. During the storm, Bennie accidentally falls into a granite quarry and shatters his leg. Even more troublesome, one of the brothers’ opponents, a shady drifter named LaBrecque, simply vanishes in the snow. Suspicion for the disappearance falls naturally on Littlefield, who doesn’t help matters when he takes off without a word of explanation.

In spite of his injuries, Bennie undertakes a search for clues to his various puzzles. What really happened during that paintball game in the blizzard? Did LaBreque flee, or did he die? What does Littlefield know, and where has he gone? As Bennie pushes for answers, he runs afoul of LaBrecque’s thuggish friends, but he unexpectedly finds himself helped by three female allies — his twin sister Gwen, his bright new flame Helen, and Littlefield’s own flamboyant girlfriend. Inevitably, he finds himself trying to decipher his bizarre childhood, hoping to discover in his family memories some understanding of where their lives all went awry. With each remembering he is provoked by the possibility that there might have been some presentiment of Littlefield’s strange and possibly criminal behavior.

Robinson, who grew up in Maine and lives in Portland, won both a PEN/Oakland-Josephine Miles Literary Award and a Whiting Writers’ Award for Officer Friendly, and that same barbed diction and mordant humor are on display in his novel. Water Dogs is a mystery in the most intimate sense — an inquiry into how well we can ever know the moral landscape of another human being, even our own brother.