I had a player jump at an opponent two-footed from distance, breaking his leg - match abandoned while we wait for the ambulance. Players are then milling around while I send the away player off. One of the home team players said something to him (not offensive so no need for any action) as he walked off. His father, who was a spectator, then came on and head-butted the home player. I had to go to the local station to give a statement about the head-butt.
I found the whole situation ok, possibly because the home team were either Customs officers or Police officers, so they were quite keen to make sure the offender got what he deserved!
Basically the officer who took my statement just asked me about what happened and made notes as I answered, then wrote down the incident as I had described it from my answers. I was then asked to read it and sign to state that this was how I remembered it.
I had made sure I had plenty of notes on the day anyway, marking down relevant positions on the FOP while they were fresh in my mind. They're not trying to trip you up, so if you don't know the answer to something then just say so. Otherwise answer honestly and you'll be fine.
In my case, I had to go to court as well, but there were a lot of witnesses apart from me, and by the time they got to my evidence the case was pretty much done and dusted so no problems.
Ten years before the incident I'd been playing for the away team when the father had also come onto the FOP during a stoppage and head-butted the Referee, so he had previous.