My friend's sister killed her boyfriend!!!!?

My friends sister and her boyfriend use to go to my school. They both changed school because something happend where they had become the most hated people in school (something about them snitching on someone popular or something). Then I come to school today an on the announcements they say that he was stabbed 17 times by my friend's sister. All my friends are crying because they were friends with him and my one friend whose sister did it is upset because her sister is now a MURDERER!!!!!! I dont know what to do and I feel like this isn't real, a bad, bad NIGHTMARE!!!!