Dark Assassin

On a patrol boat near Waterloo Bridge, police superintendent William Monk notices a young couple engaged in an intense discussion. Seconds later, the two plunge to their deaths in the icy waters of the Thames. Was it an accident, a suicide, or a murder? Ever the investigator, Monk learns
that the woman, Mary Havilland, had planned to marry the fair-haired man who shared her fate. He also discovers that Mary's father had recently died in a supposed suicide. But Mary's friends share their own...