Tonton Streaming Thorne (2010) S1E1 - Sleepyhead (1)

Three women are found murdered, their killer having induced them into having strokes. A fourth is still alive, and may be able to identify her assailant, except she is unable to communicate as she has been left with locked-in syndrome. DI Tom Thorne concludes that it was the killer's intention to leave his victims incapacitated, not dead.