The Silent Women - Sara Blaedel

Homicide detective Louise Rick chases a terrifying serial rapist who meets women on a popular online dating website in this fast-paced #1 internationally bestselling thriller from Sara Blaedel, whose books have sold over 3 million copies worldwide.

An online flirtation can have horrific consequences, as Detective Louise Rick discovers when she is called to an idyllic Copenhagen neighborhood where a young woman has been left bound and gagged after a profoundly brutal rape attack.
Susanne Hansson met her rapist on a popular dating website. But the man is hiding behind a labyrinth of false pseudonyms, and neither Susanne--nor the police--have been able to trace his true identity. With the internet as his playground, the rapist will almost certainly strike again if Louise can't unmask him before it's too late.
Incredible suspense and a diabolical series of twists take Sara Blaedel's wildly popular series to new heights.