My maintenance man got into a verbal exchange with a tenant. He and witnesses say the tenant "lunged" at him 3 times without striking. The maintenance man then beat the guy up pretty bad breaking his own hand during the fight and leaving marks, cuts and bruises on the tenant. No charges filed (don't know why). The maintenance man also entered one of the apartments without permission despite me telling him not to. there are other issues but these are the most serious. We have no formal contract. He performs repairs and such in exchange for rent (I do have a written document stating just that). He handed me a bill for almost 10k $ stating that he had done a lot of extra work over the last year. Do I have to pay? Can I legally "fire" him?