The Shadows in the Street (Book 5 in the Simon Serrailler series)

Simon Serrailler has just wrapped up an exhausting and difficult case for SIFT – Special Incident Flying Taskforce – and is on a sabbatical on a Scottish island when he is recalled to Lafferton. Two local prostitutes have vanished and are subsequently found strangled. By the time he gets back, another girl has disappeared. Is this a vendetta against prostitutes by someone with a warped mind? Or a series of killings by an angry punter? But then one of the Cathedral wives goes missing, followed by another young married woman.