In the beginning of the movie, it shows Heather and somebody else seems to be holding the camera to film her, but this can't be right, because Josh and Mike show up a later on.
Actually, judging on the position of the camera and the movement (if it were a person, the camera would have jiggled from general moving around), I'd have to say she put it on a camera stand and pressed "record."
No, actually, it is a roommate/boyfriend because if you listen carefully, you can hear the person talking to her. It may have even been a woman, I can't remember.
At the web site it mentions she has a male roommate. In the begininng of the film there is a guy talking into the camera, so it's obviously not on a stand. It's her roommate.