Visible crew/equipment: If you look really close in the background as the killer throws Cici off the balcony, you can see someone sitting in a tree, wearing black, with a camera. (00:33:35)
Visible crew/equipment: When Cici is killed, just before the killer throws her off the balcony there is a visible member of crew/stunt's head (this has been edited out in newer versions, but remains visible in others). (00:33:50)
Visible crew/equipment: Hearing about what happened at Omega Beta Zeta, Derek tells Sidney "let's get you home" and when she gets inside the camera comes closer to Jerry O'Connell for a dramatic shot...that catches in frame part of the stage light. Actually spotted by Wes Craven during the DVD commentary track. (00:38:35)
Chosen answer: In real life, they'd have known there was a phone call involved. They would have known her boyfriend was killed. They could have easily pieced together that the killers played a cat and mouse game with the Drew Barrymore character. But that doesn't account for all the details. Anything else would be speculation. My speculation: Maybe Billy Loomis kept a diary.
K.C. Sierra
And rumor has it that Stu didn't die that he may still be alive.