Evelyn A. Sainz was a pre-War resident of the Sierra Madre Casino.
Background
Evelyn Sainz sent an emergency e-mail to her boyfriend John Lester on the night the bombs dropped, when the holograms massacred the guests. The message can be read on Tampico's front desk terminal.
Appearances
Evenlyn Sainz does not actually appear in any game but is mentioned in Fallout New Vegas' add-on Dead Money.