John K. Lester was a pre-War resident of the Sierra Madre Casino.
John Lester rushed to aid his girlfriend Evelyn Sainz on the night the bombs dropped, when the holograms massacred the guests. This can be read on the Tampico's front desk terminal.
John Lester's skeleton appears in the Fallout: New Vegas add-on Dead Money, next to the password to the Tampico's front desk terminal. His skeleton is lying on top of his girlfriend's skeleton.