Fall the Shadow: Part 1 - S6.E3

Tony attends a conference of psychologists, where he is a guest speaker and where he meets an old friend Rachel White, another delegate. He has drinks with her in her room but leaves before having sex. Next morning she is found dead and he was the last person to see her alive, marking him as a suspect. Then another psychologist is also murdered whilst Alex investigates a serial killer whose targets are prostitutes.