What exactly is a camerahead?

I was walking home, just through a nearby gulley. It wasn't that until I stumbled upon a weird pile of rocks and a torn box. The box itself had a torn envelope, a VHS tape, and a picture taken in 2008 of the suspecting creature's corpse. First I had to go with the envelope. It had some writing on it.
There was a few notes referring to the creature:

I killed a camerahead.
They took away trevor. It's not your choice anymore.

The text was clearly hand-written by someone. It couldn't have been some mysterious creature. It was clearly a human because of the handwriting.
Next comes the VHS tape. The only writing on it was "Camerahead." I didn't know what this would mean so I put it in the VCR and there was a ton of static.
There was a few clips shown, but there were these two clips that made me curious.
There was a scene where something was chasing after two people in a forest. If I had a guess, one of them were trevor, which had been mentioned in one of the notes earlier, with a mention of him being taken away.
There was another scene where a figure emerges through the static, laughing. That figure had a completely back body with a slightly disfigured mask. Was he the leader of the cameraheads? Who is he?
The tape ended, lasting 9 minutes. I had a look for the picture from 2008. It showed a forest, with a corpse of one of the suspected creatures, laying there with a severely disfigured body. There was a pool of blood from the body.
I just had to take the box to my home to study about them. What exactly are they? It would've been silly if they were some random creature with a camera for a head.