ANY NJ LAWYERS OUT THERE? THIS CASE INVOLVES A FALSE RAPE CHARGE?

[NJ76]

A friend of mines applied for a California State Police job. Everything was almost a go and his recruiter called him and said that there is a rape charge on his record. He was floored. He almost had a stroke. My friend works for a police department in nj. Just graduated from college with a degree in CJ. Clean as a whistle. Not even a speeding ticket. He never even knew that he was suspect. The girl engaged in a "train" with him and some frat brothers. She is known as the campus S**T. Anyway he never went to court. He was never questioned. Never been contacted by the police. NOTHING! They said the girl went and dropped the charges....but its still showing up on his background. Which is weird because he was never charged with anything. He even just renewed his passport. One of his frat bro's just got into med school. They have to run a background check before you can be accepted into med school. Anyway what should he do. This girl lied. He was never charged with anything...but a rape charge is on his background. My friend is sooooooooo hurt. Can he sue the girl and the police department?