Deadly Fun by Pamela M. Richter
Working in disguise and undercover with an assumed identity, Lo uses her unusual beauty to ferret out information. She works for an independent agency associated with the FBI. Her boss knows she has a checkered past but she’s also smart and independent. Lo has a reputation–she always gets her man.
Her new job involves a cruise to the Bahamas with her boss to investigate an enforcer for the Mob. But this will be like no other job she has encountered. By the end of the voyage she has chased suspects through the tropical islands, been in physical confrontations with knife, fist and firearms; the deck is awash in blood. Can she survive the deadly fun cruise–and her boss, who may prove even more deadly than the Mafia men she uncovers?