Calm Waters by Lena Bourne

Calm Waters Run Deep.
Young men and women stabbed through the heart and left posed by the river in the night. A killing spree that’s been going on for decades. In most of the cases, the official explanation is that the victims were just in the wrong place at the wrong time. But investigative journalist, Eva Lah believes the murders are the work of a serial killer–one that’s successfully avoided detection until now.
Evidence is thin on the ground and resistance by local authorities to reopening old cases is staunch. But Europol Investigator and Eva’s partner, Mark Novak, agrees to have his task force look into the cases. The hunt is on.
But Mark and Eva have woken a sleeping monster and now that he’s out in the light, anything can happen.
And will.