How do I legally get my abusive roommate out?

Question Details:

My husband and I signed a lease with our roommate on a new place. The moment we moved in, he completely changed. Verbal abusive, screaming, even threatening my husband through texts. My husband got fed up when he left he front door wide open one night and didn't care, anyone could've come in. So that night he calmly told him he's no longer comfortable with the arrangement and he offered him his deposit back. He's scary and we don't feel safe. We finally got him to say he will leave in a text. Now he's making demands. Important Notice