WhoDunnitAI

You play this one by talking. The first case, Death at Blackwood Manor, hands you a poisoned patriarch and five guests. The work happens in an interrogation room where you question the suspects out loud in your own voice. They answer through a live voice model, so there is no menu of prepared lines: you press someone on an alibi, notice a contradiction, sit on it, and come back to it later. When you are sure, you accuse a suspect to their face and the case closes.

Interview time is free but capped. Adding your own OpenAI key lifts the limit. The site is upfront that the voice minutes cost real money, and donations are accepted but optional.