If you find that your child has become at risk online do not panic. There are steps you can take to protect your child and possibly catch the perpetrator. They are probably very frightened and need to be reassured and know they are safe.
Lectures can wait.
Ask them if they know how the person got the personal information. Tell your child you will not be angry, you just want to protect them. Save all information that you have. This includes emails, guestbook entries, bulletin board messages, images, files, etc. This information is used by the law enforcement authorities to track down and locate the perpetrator.