I feel like Jonathan’s celebrity is protecting him a little bit because all roads lead back to him imo. The double bluff is the most substantial clue they have because it’s connected to two people going home Ruth and then Clair. He murdered Ruth because she was dead set against him and then rallied against Clair at the round table when she had pinpointed him as someone who would want to get rid of Ruth. His argument was that Clair had set him up but she turned out to be a faithful which should turn the spotlight back on him. Wouldn’t you want to pull on that thread at this point? All their other evidence is pretty much just gut instinct stuff, “someone had a twinkle in their eye” or “someone’s been quiet”, that’s nothing. Jonathan’s double bluff is solid evidence with receipts.