Billy Joel has Paul McCartney to thank for helping him track down a woman who has been charged with cyber stalking his daughter.

McCartney recommended the specialist private eye who helped identify Sheryl Finley as the person allegedly threatening Alexa Ray Joel  on Facebook.

McCartney's involvement comes to light months after the suspect was arrested and charged with felony stalking.

According to the New York Post, the Piano Man enlisted the help of the former Beatle after 27-year-old Alexa Ray was bombarded with more than 60 Facebook messages.

She was eventually found naked in the Austin, Minnesota woods, the Post reports.

Court records allege the 40-year-old Finley sent Alexa Ray messages that included scenarios involving “pedophilia, sadistic-sexual behavior, violent physical assaults and murder.”

The content petrified the budding songwriter who was reportedly afraid to leave her home in Manhattan.

And with good reason. Austin police captain Dave McKichan told KAALtv.com: “We certainly see a lot of harassment-type cases with the advent of Facebook and Twitter.

“Often times those networking sites will lead to more serious crimes.”

A source told The Post that Alexa Ray’s mom was particularly concerned. “Her mother, Christie Brinkley, was terrified that someone