The Final Proof
In the fridge we can see the ampoule of Anduran. Thomas was sure that no one could access his room (it’s stated in the email from Robert), but he accidentally included the stolen medicine in a photograph he was sending for the magazine article. That’s the final proof that indicates Thomas is the potential killer.
We remind you that we’re not making conclusions about the killer, but rather helping police to find potential suspects. The court will make the final decision.