Gains a star because the heroine is a doctor. The story is set in America, in a NYC hospital where a nurse is shot dead in the parking area. Two weeks later, another nurse is so killed.
The police seem completely negligent from the start. They don't do the obvious thing to eliminate any potential suspects.
Two thirds through, the lead detective starts a fling with the doctor he's been questioning every time he comes to the hospital. A hospital which has seemingly no HR department, so the busy doctor is going with the detective to tell people their loved ones are dead. The detective is absolutely compromising his investigation with this affair, they should have waited until the case was concluded or he would be torn apart in the witness box.