(At about 1:57) The poison was dissolved in peanut oil. Henry tells Shawn that "his hands would look like baseball mitts if he got anywhere near that stuff" While Sal has a severe peanut allergy, peanut oil is highly refined and does not contain the allergen that (most) people with peanuts are allergic to, meaning he could have been the murderer.
Kirsten Nelson (Chief Vick) clearly says, "The most powerful businessman in the state is the target of an assassination and one of my people helped planned it." (The closed captioning says "helped plan it," but she definitely says "helped planned it.")
At 20:15, Shawn meets Bonaventure and puts his hand to his head to communicate to Bonaventure that he has a psychic vision of him being in danger. He does this in front of Jules and Lassie. However, Shawn was just with Juliet and Lassiter when he figured this out and they would know that it wasn't a vision.
Shawn mentions the treadmill seen in the opening credits of "The Jetsons". However, the treadmill actually appears in the closing credits.