My experience in mi. is that eviction is usually a small claims matter so you do not need to hire a lawyer unless the amount limit for small claims is exceded. You should go through the normal course of eviction: informing in writing to quit or pay (on a state approved eviction form, then serving in person or by certified mail the formal eviction. If they claim to be moving by a certain day, then inform them in writing that you will be there the morning after they plan to move out with the police for security reasons. That often does the trick. Regardless, you should start a proper eviction asap. just in case they don't, for documentation to collect damages & back rent in court.