Certain Prey (2011) made for tv usa channel
Minneapolis Deputy Police Chief, Lucas Davenport, has to face off against a duo unlike any he's ever encountered; a lethal hit woman and a ferociously cunning killer determined to hunt him down.
Tat plays one of the roles above, either hit man or killer.
Looks like in the trailer she is wearing disguises so this may be what got her the role in OB.
I am going to check it out, I like harmon on Ncis so with them 2 it should be ok.