Concur with TXAZ. Treat the drawing the same way you would if you had actually fired.
It also depends on the Jurisdiction you are located in. In my case, if I were involved in an incident in Paul Babeu's jurisdiction in Pinal County AZ I would call 911 report the incident and then call my attorney. His advice is to inform them I am shook up and will schedule an "Interview" at a later time.
If the incident occurred in my home county, Apache County, I would speak freely as i am not on the Sheriff's enemy's list.