In this video, the US Marshal says the passport was not fraudulent and was a legitimate passport issued to someone else "that she used because she looked very similar to that specific individual." Well, I think we can read between the lines here and guess whose passport she used.
She also dyed her hair dark brown and cut it shoulder length. When she was apprehended, she had a bandage over her nose which she said was from a recent surfing accident.
ETA: The US Marshal also says that KA signed a log-in book at a yoga studio in Costa Rica under the same alias she was traveling under.
Given what we know about her New York connection, and the statement from the guy who claimed he had seen KA at the Haven right before everything blew up, and given the short period of time that she was actually in NY, the most obvious conclusion, and the one that I am sticking to until I see facts to dispute it, I feel comfortable that the passport she used of someone who looked very similar to her, belongs to her sister. I would not rule out more charges in this case, though I think probably the threat of more charges will serve LE better than actually pursuing them.
I admit I am surprised that KA cut and colored her hair. I think her hair was her crown, and it surely must have hurt her to cut it. I would have thought she would probably cover it with hats or a wig. And if she undeed had plastic surgery, it seems likely it was no more than a nose job, hence the band-aid that she got from the "surfing accident".
Finally, of all the smooth moves she made that allowed her to escape to Costa Rica and stay on the lam for some 50ish days, did she really get so complacent as to think she actually HAD gotten away with it, and felt comfortable enough to start living life using the alias she traveled under? Wow! That log-in at the yoga studio may have been the slip-up that nailed her. JMO