Rewatching The Mentalist after years, I noticed a detail that made me ask a question.

To be precise I'm talking about episode 13 of the fourth season, when they find the guy from the morgue dead and wrapped up they assume it was Red John but you don't see anywhere the smiling face made in blood that Jane is from the beginning that says is John's signature and nobody seems to notice. Now, maybe later it will be seen that it wasn't him but one of his "friends" and I don't remember it but this way Patrick shouldn't have any doubts about the fact whether it was really John?