Legal Question in Real Estate Law in Illinois

You have to give him a 30 days notice.

Typically, you would follow the same eviction process as if you had rented an apartment to someone. You begin with notice, which is probably 30 days in this case. Depending on how you feel about the risk, you may want to have the sheriff serve the notice, although that is not required. You can find information in the Illinois Forcible Entry and Detainer statute. If the notice does not result in his move, then you have to file an eviction lawsuit, at which time you would have him served with a summons and complaint and set a court date.

For the best chance at this going smoothly, without delays, use an attorney. If he does commit a crime, call the police (damages the home or your belongings, assaults or batters you, ...).

Since you are living in the same home, that may open some avenues under the Order of Protection statute, even more so if there is any history or impression of a relationship (which you have not indicated). This may, however, be a tricky fit to the statute. You can discuss orders of protection with a family law attorney. It may be worth doing so, as it sounds like you have some concern as to how things would proceed.