A guy rents a workshop in the desert. His girlfriend is skeptical. There is a large static caravan/mobile home on site and they move in. He hears a noise underneath and goes to look. Something attacks him. She is kidnapped inside the mobile home.

The guy is then inside the workshop, looking at his girlfriend on a video monitor held in a chair. An unseen guy tells him he must kill people to save her. Police investigate and he kills them, he adds body armour/a helmet from the stuff in the workshop.

Later in the film he drills holes in someones legs and bolts their bones to a table. The original girlfriend is rescued by police. But a chase ensues through the workshops yard.

A man drives off laughing, it is implied he was the unseen guy.

This is one I saw a while ago. I have tried searching for ages and cannot find anything. It is so annoying because the name is in my mind and wont come out!