Unseen Strangler 5

In Louis Conner's The Unseen Strangler 5, investigator Amara and a network of international operatives uncover a chilling new phase of systematic predation hidden deep within the maintenance tunnels beneath London and other major European cities. As they trace a trail of precise numbered markings and hidden storage spaces, they discover that a distributed network of killers has spent over a decade using the continent's transit infrastructure to conceal hundreds of victims. Ultimately, Amara and her team must confront the horrifying reality that urban infrastructure itself has been co-opted to silently enable, document, and protect these atrocities.