A gunshot. A body in the library. Six people in the house, each with an account of where they were and what they did. One of them is lying — and the lie can only be caught by comparing what someone says they were doing at the moment of the shot against what someone else says happened straight afterwards.
Each suspect can be asked four questions: Where were you?, Was anyone with you?, What were you doing when the shot was heard?, and What did you do when you heard the shot?
The third question asks about an action already in progress at the moment of the shot — a scene, an alibi. The fourth asks for a sequence of things done afterwards — a reaction. They call for different grammar because they're asking about different kinds of time: one moment, interrupted, versus one thing after another.
In Join the investigation, question all six suspects, study the house plan, then accuse the culprit — and prove it by picking out the two statements (from different suspects) that don't add up.
Print the house plan, the suspect list, and the transcript so far, and work out the case away from the screen.
Question the suspects, study the house plan, then name the culprit.
Who fired the shot?
Which two statements — from two different suspects — don't add up? Pick both.