Darkness falls / Robert Bryndza.

Kate Marshall's detective agency takes off when she and her partner Tristan are hired to investigate a cold case from over a decade ago. Twelve years previously, a determined young journalist called Joanna Duncan exposed a political scandal that had major repercussions. In the fallout she disappeared without trace and was never found. When Kate and Tristan examine the case files, they find the trail long cold, but they discover the names of two young men who also vanished at that time. As she begins to connect their last days, Kate realizes that Joanna may have been onto something far more sinister than anyone first believed: the identity of a serial killer preying on the people who few will ever miss.