The five most popular story-specific questions people ask about Death Valley, Series 1, Episode 4 are:

1. Who was responsible for the murder of Menna Hughes in the amateur dramatics group?
2. Why did John decide to take a role in the theatre group's next stage production?
3. What significance does Menna Hughes' illness and her will have on the investigation?
4. How does Janie's ambition for a DI promotion influence her approach to the case?
5. What personal challenges do John and Janie face during the investigation, and how do these affect their actions?

These questions focus on the murder investigation details, character motivations, and personal developments within the episode's story, as described in the episode synopsis and recaps.