Cold Dark Water — Susan Lund

A cold case from a decade earlier. The body of a missing teen in a submerged car in the cold dark waters of Lake Washington. The reopened cold case becomes personal to amateur sleth and crime reporter Tess McClintock, who went to school with the missing girl. Together with former FBI Special Agent Michael Carter, Tess goes on the trail of the cunning serial killer operating in King County, Washington. The killer is smart enough to vary his MO and hide his tracks. As a result, he's escaped detection despite hiding in plain sight, picking off vulnerable young girls who are easy targets. When Kate and Michael start to close in on him, his carefully crafted cover starts to unravel and he slips up. To catch and stop this conniving killer, Kate and Michael must risk their lives to bring him to justice.