It was in MPD's jurisdiction. City and county are two separate agencies so no conflict of interest on the face of it.
I bet they had no other choice but to give the prosecution to some other county, though. Would have been a huge outcry otherwise.
It happened at a Whataburger. Apparently the Sheriff walked in on an altercation (not sure if he was called to come..). Anyhow, one the two men fighting was Sheriff Brown's brother, (he been tossed to the floor.) There's more to it, but that's the jist of it. I saw an article floating around, I'll see if I can find it.