Reversal of Fear by J.T. McCalla:

Psychologist Robert McMahon flees Chicago, one step ahead of a murder contract issued by Peter Vinesco, the feared mob boss. McMahon escapes to California, where he begins a new life using the identity of Shawn Rappor, his best friend in Vietnam. Rappor builds a life, a practice, and falls in love with a stunning concert pianist, Charlynn Powell. After six years of constructing a new existence, he discovers that a surveillance team has him under a microscope. Rappor formulates a plan to first eliminate the surveillance thugs and then the Vinesco crime family hierarchy. Murders, kidnappings, confrontations, and plot twists, flavored with a touch of romance, humor, and memorable characters keep the action moving to a shocking and exciting climax.