Get the address where you should mail the complaint letter. This is generally listed on the police department's website or you can call to find out this information.
Type your name and contact information at the top of the letter. Should the police department wish to contact you with further questions, they can find your address, email and phone number here, at the top of the page.
Add the name and address of the police station to the letter you're writing.
Put the date that you're sending out the complaint letter below the police department's address.
Explain the nature of your complaint in the first paragraph. Talk briefly about the issue you have with the department, staff member or officer.
Detail your complaint in subsequent paragraphs. For example, if there was an issue involving an officer at your home, state the date and time of day, why the officer was called and what event proceeded his arrival on the scene. Give these details without comment. Just present the facts, as they occurred.
Type and sign your name at the end of the complaint letter. Keep a copy of the letter for your own records.