I has an anonymous stalker...?

i was on AIM one night and this chick starts talking to me...she says she knows me and she obviously does...she knows EVERYTHING ABOUT ME from high school to now. she also mistakenly thinks that one of my friends and i are madly in love because we listened to music together and we hugged the night that i found out my grandpa died...shes wierd and she also knows everything about my friend. she brings up horribl secrets from my friends past and wants her to die...by suicide...this chick is messed up...this has been going on for two weeks and we think we might know hu it is....but WTF?!?!