Black Ball
Superstar
The matter was resolved in his mind....and then season 5 happened. Jesse has spent this whole season second guessing everything he knows about Walt. Like I said earlier in the thread, I don't think we needed a moment specifically for the ricin....like "he lied about Mike, he lied about feeling sorry for Drew Sharp dying....I bet he's lying about the ricin too!". I mean....Jesse just came from a meeting where he accused Walt of constantly manipulating him, killing Mike, and possibly plotting his death. That scene is literally right before he goes to Saul's office. He gets pick-pocketed a second time....it's not to think he'd piece that together, with the mind state he was in, and the accusations he'd just made.
Fred.
Jessie has been leary about Walt for a while now. But Jesse also believes he has a handle on when Walt is lying to him because it usally makes sense. Like Jessie never fully believed Walt about Mike or the little kid. He had his evidence in his own mind, and basically gave Walt the mental on those topics. Jessie doesn't think everything Walt says is a lie though. Jessie believes in his own intellect and the shyt made sense to him about the whole Brock incident at that time. If Brock had actually been poisoned with the Ricin or Jessie never found it at his house, then it would make sense that he would second guess that whole incident. Finding the Ricin in his home would seem to be more convincing than a passing thought about Huell pick pocking him once before.