Murder below Montparnasse - Cara Black

When Aimee's long-term partner and best friend Rene leaves their detective agency for a new job in Silicon Valley, Aimee knows she can handle the extra workload. At least, that's what she tells herself. But all bets are off when Yuri Volodya, a mysterious old Russian man, hires Aimee to protect a painting. By the time she gets to his Montparnasse atelier, the precious painting has already been stolen, leaving Aime smelling a rat. The next day, Yuri is found tortured to death in his kitchen. To top it all off, it looks like Aimee isn't the only one looking for the painting.