Lilith took possession of this girl at an unknown point in time. After Sam and Dean Winchester managed to fight off an army of demons she sent, Lilith arrived at the police station where Sam and Dean's allies were. She approached Nancy Fitzgerald with her vessel's mother and asked about Sam and Dean with child-like glee.
When Nancy asked her name, she revealed that it was "Lilith", surprising Nancy, Victor Henriksen and every other survivor present. Although the people had been warned about Lilith, they were unable to prevent Lilith as she revealed her white-eyes to them and engulfed the station in a bright light. She proceeded to torture everyone present, with Victor as the last victim.
At the end of it, Lilith reduced the police station to rubble, much to Sam and Dean's horror.