Melissa Dorn is the daughter of Dr. Sylvia Chalmers and the half-sister of murdered Marine Thomas Dorn. Agent Leroy Jethro Gibbs flirted with her during the investigation into her half-brother's death but all hopes of a potential relationship came to an abrupt and permanent end when it was discovered that Melissa and her mother had scammed an insurance company out of money after Dr. Chalmers had killed PFC Dorn.