I live in the area and heard a story passed on from a relative of an early reaponde: One of the surviving girls had a stalker, and she was scared that night for some reason so she slept with her roommate. They heard something at the door at one point and they both hid in the closet. The killer looked in that room, didn't see anyone, walked to the other room (or vice versa), then went upstairs or wherever the other roommates were and started killing.

They supposedly stayed in the closet and called a friend to come check out the house the next morning. That guy went in, then ran out when he saw the carnage and passed out in the front yard. That was the original emergency call, I guess, for the dude who passed out.

Sounds pretty weird to me that they would just sit in the closet for hours and hours, maybe its not totally true, but that's the story I heard.