The police and the district attorney do not determine innocence or guilt. They determine probable cause--a judge and/or jury determine guilt or innocence. Deciding whether or not you were guilty is NOT the function of the police or the DA.

Also, a guest for five months is not a guest--it is a tenant whether or not they are on the lease and you would have to go through legal eviction to have them removed.

You have a right to defend yourself in your home, but wasn't that charge dropped?