Clearly Partridge faked his own death because he is Red John.
Why did no one come when Theresa Lisbon called for assistance? Because Red John told them to wait until he told them it was okay to show up. Red John made sure only his followers would arrive at the scene so he could fake his own death. Theresa was there to distract Patrick Jane from inspecting Partridge's body. That is why he drew the smiley on her face.
In S1e2 he chatted up Van Pelt to screw up Patrick Janes trap. It created a distraction that led Lisbon away from Jane in the hotel room, so the two killers still showed up with their victim and almost killed Patrick Jane.
In S6e3 it shows he's just as good as Patrick Jane when it comes to reading people, when they deduced the dead guy was a pizza delivery boy.
Everyone remember "Tyger Tyger"? The poem that Red John recited? Well, the author of that poem is William Blake (often connected with Serial kiillers because of his dark christian-based work). Well, Blake is quoted by another character, once, in the entire series, at the end of a case, NOT in the presence of Jane. Blake was quoted by Bertram, and Cho picked up on the fact that the author was Blake, and then this was NEVER mentioned again. A perfect piece of dramatic irony, a clue that would give Jane everything he needs to know, but Cho didn't know to give it to him.