The Devil by Ken Bruen

KEN BRUEN was born in Galway, Ireland. After turning down a place at RADA, and completing a doctorate in Metaphysics, he spent 25 years as an English teacher in Africa, Japan, South East Asia and South America. An unscheduled stint in a Brazilian prison where he suffered physical and mental abuse spurred him to write and, after a brief spell teaching in London, he returned to Galway, where he now lives with his daughter.

Refused entry into America, P.I. Jack Taylor thinks an encounter with an overly friendly stranger at the airport is to blame. Jack resumes his old life in Galway, but when he's called to investigate a murder, he remembers the man from the airport. Is the stranger really who he says he is?