HELP ! I need a letter telling tenant I wont renew lease

[Rochelle Wilkinson]

Hello.. I have a problem tenant who we know has stolen from everyone in their building. The daughter is on drugs ( she has been seen by myself and others grabbing at objects in the air that aren't there and making circles on the wall in the hallways with her hand  and the mother said she is probably one the stealing and that she is on drugs)  They also have a son who is about 14 who other tenants tell me they kick him out of the apartment and he hangs out back and urinates by the back door and drinks beer all day.. then he passes out in the laundry room.. not really the people we want in our buildings.. can anyone give me a sample letter telling them we are not renewing their lease? and do I have to legally give them a reason why? and is the law 90 days notice before the date of their renewal? ( their lease renews in October) Thanks in advance