Dana was the courier used by Ziva David to pass phony passports to Ari Haswari so he could escape the country after killing Caitlin Todd; an act he denied committing.
Tony, following Ziva, figured it out and acted like a goofy guy who was part of a nudist society in order to stall her to allow Gibbs to intercept the passports. She rejected his advances, claiming to be married.
Unfortunately, Tony failed to stall her and she presumably manages to deliver the passports to Ari.
Tony's boss, Leroy Jethro Gibbs attempted to tail Dana but was thrown off course when the Vintage Morgan that Dr. Donald Mallard arrived on scene and as Gibbs searched the Morgan for any sign, Dana was driven off into the night and was never seen again.