Spare Change (2007)

The "Spare Change Killer" leaves three coins by each of his victims. It seems he's resurfaced after some 20 years, and Boston PI Sunny Randall is called to assist her dad, a former cop who investigated the original murders. But when one flirty suspect gives her the willies during an interrogation, she begins meeting him socially to confirm her suspicions that he's their man. It's a potentially explosive plan, but Robert B. Parker spends more time detailing the creepy charge between Sunny and her Malkovich-like mark than in building tension. As a result, Spare Change feels less like a whodunit than a methodical march toward a foregone conclusion. With naughty bits, of course.