Anna is the main villainess from the NCIS episode 10.16 "Detour".
She was portrayed by Valerie Cruz, who also played Dr. Levine from Grimm.
Anna was the leader of a criminal trio who abducted Ducky and his assistant, Jimmy Palmer. They were later taken to a cabin in the woods, where they were ordered to work on the body of a Petty Officer who was actually a Cuban mole. Anna's true mission was to find a flash drive that had important info, and she acted on false information provided by Jimmy on her quest.
The info led to Anna being caught by NCIS, while also learning that the locker she was searching belonged to Jimmy, as part of his ruse to catch her. Anna was later arrested.