The Fall the Light
Her mother and father were providing food to Fort Domas, after the food stopped you went to investigate. Your gorup found what you believed to be Anna and sent her back to Quil while you rushed off on another rescue mission.
Later on Anna was actually found while rescuing Aramys, She was being guarded by a pale one. She decided to follow your group through. Later it was discovered that Quil found out about the impostor Anna and killed her.