Her music isn't as widely known as her famous father's, but Alexa Ray Joel -- otherwise known as the 27-year-old daughter of Christie Brinkley and Billy Joel -- still has some fans of her own. In fact, one of them recently took things a little too far.

The New York Post reports that Alexa was recently the target of a cyberstalker who sent her a barrage of disturbing Facebook messages, some of which, court records claim, include discussion of "pedophilia, sadistic-sexual behavior, violent physical assaults and murder." According to the paper's source, the messages left her "afraid to leave her Manhattan home."

Understandably annoyed, the elder Joel hired a bodyguard to protect his daughter before reaching out to his friend Paul McCartney to see if he could give him the number for a good private eye. According to the Post, McCartney "recommended a Europe-based private-security firm" which is -- and here's the key phrase -- "not bound by the same legal restrictions as the police."

Sure enough, the investigators turned up Alexa's stalker -- and when they did, she happened to be naked in the woods of Minnesota. After being taken into custody, court records show that the woman claimed her threats were not meant to be carried out "during this life" and expressed a hope that Alexa would eventually meet with her.

Moral of the story? Billy Joel might be the pop songwriter who recorded ballads like 'Just the Way You Are,' but before that, he was a Long Island street tough and a professional boxer, and old habits die hard. Don't mess with the guy.