Fictional Murders: Aren't You Glad You Didn't Turn On The Light?

Kelly and Danny were complete opposites. Kelly was a bookworm, who was seen as smart and responsible and Kelly liked to live life on the wild side and was seen as a party girl.  Despite their differences, the two girls were best friends. When they had gotten to college the two had roomed together in the dorms.

It was getting close to their first midterms of college. Danny, being who she was, wasn't worried about the midterms. She was invited to a party by a guy she liked and really wanted to go. When two got back the room they discussed their plans. 

Kelly was, of course, going to stay in the dorm and study. Danny wanted her to come to the party and enjoy the night but wasn't successful in convincing Kelly. When Danny left she felt guilty she wasn't going to stay and study, but partying is a good way of releasing stress. 

It was already 3 a.m. by the time Danny got back. The lights were off and she figured Kelly was sleeping. She could hear her toss and turning on her bed and didn't want to wake her if she was already having a tough time sleeping.

In the morning Danny woke up to a horrifying sight. Above Kelly's bed written on the wall in blood was "Aren't You Glad You Didn't Turn On The Light?" She automatically ran over and found Kelly was cold and was covered in blood.

This would mean the tossing and turning she was hearing when she came in wasn't Kelly having a rough time sleeping. She was being murdered and who knows how long the murderer spent in the room before Danny woke up.

SOURCES:
How it was told to me as a child
Urban Legends Online