A very international lot of reviews this week with a another new author for me. Written by a German, this is set in London. Two seemingly unrelated deaths of elderly isolated women are baffling police and then a man is murdered whilst his wife is out deciding not to have an affair. Add in a disgraced cop who is now a private security consultant who is tangled up with a potential victim and a lonely and socially awkward observer, The Watcher of the title. An intriguingly complex and well written tale.