Not sure I understand the marketing logic on this one, but HarperCollins has listed
212, third in Alafair Burke's Ellie Hatcher series, as free on Amazon:
212: A Novel (Ellie Hatcher)
When a bodyguard is killed in the Manhattan penthouse owned by his billionaire boss, Sam Sparks, the case gets under Detective Ellie Hatcher’s skin. But she has to set aside this unsolved crime—and her suspicions of Sparks, which land her a contempt charge and a night in jail—to investigate the murder of an NYU coed, who was being harassed online, and her roommate. Then a real-estate agent who moonlights as a call girl is found murdered after being tortured in a first-class hotel, and Hatcher and partner J. J. Rogan find a common thread in what seem unrelated cases.
http://www.amazon.com/gp/product/B003B02ON2/