(1) At the end of each investigation of a complaint, the commission shall prepare a final investigative report containing: (a) The names and dates of contacts with witnesses; (b) A summary and the dates of correspondence and other contacts with the aggrieved person and the respondent; (c) A summary description of other pertinent records; (d) A summary of witness statements; and (e) Answers to interrogatories.
(2) A final investigative report may be amended if additional evidence is later discovered.