I have a 19 year old living with me with no lease and he is not currently paying rent. I have told him he needs to move out. He has threatened other people living in the home. What do I have to do to remove him from my home?

Welcome to AMHD. Some 19 year olds have a tough time making the transition to adulthood. There has to be an acceptable level of mutual respect and civility in a household. Of course, this starts at 'the top'. Should one 'coddle' or use 'tough love'? My view is to get family counseling, and visit your library or book store. Check this: Helping my almost 19 year old daughter face the real world - Child & Adolescent Development Overview

You give them a written notice to move out, if they still don't move, you go to housing court to evict officially.

If they are threatening someone, have them report it and get a order of protection which will keep the person from legally returning.
** but only report if the threats where real and seroius

Yeesh, you evict them. Get it over with. He needs to grow up and be a man. In World War II, 17 year olds were flying bombers and he can't pay rent? Give ME A BREAK!

If he has threatened others, Call 911 NOW! Otherwise, YOU CAN BE SUED for negligence.

(Did I make my point?)