 Lassiter is very protective of his partner, Juliet O'Hara, and sees her as a little sister, and even promising during a polygraph (lie detector) examination to physically hurt Shawn if he emotionally hurts O'Hara.Omundson says that while Shawn and Gus' increasing presence in police investigations is a great annoyance to Lassiter, "I think, secretly, he doesn't mind them too much because it always gives him a nice challenge.