Interesting camera angle

I was just mindlessly watching a TV drama 'The Killing' when a really cool camera angle was used. There were two characters conversing using medium shots but one character was in a shadow and a computer screen was used to shine light on the other. This gave the effect of the unknown as the character had a bold outline yet no features were seen. I found it really quite scary and useful if my motives for my opening was the genre of horror.