Aren't You Glad You Didn't turn on the Light? AKA The Roommate's Death

Example 2

I heard about a girl who went back to her dorm room late one night to get her books before heading to her boyfriend's room for the night. She entered but did not turn on the light, knowing that her roommate was sleeping. She stumbled around the room in the dark for several minutes, gathering books, clothes, toothbrush, etc. before finally leaving.

The next day, she came back to her room to find it surrounded by police. They asked if she lived there and she said yes. They took her into her room, and there, written in blood on the wall, were the words, "Aren't you glad you didn't turn on the light?" Her roommate was being murdered while she was getting her things.

(I've heard this several different times. Each time it was at a different university.)