Detectives investigating the murder of UnitedHealthCare CEO Brian Thompson reportedly found shell casings with the words 'deny', 'defend' and 'depose' inscribed on them. Police sources told ABC News that casings were found at the scene with the cryptic messages left on them. Detectives are now working to determine what the words mean and if they could possibly hint at a motive for the slaying of the 50-year-old. Officers are still searching for the unknown assailant who gunned down Thompson outside of the Hilton Hotel in Manhattan on Wednesday morning. Authorities say he fled the scene on foot before then making...