I'm always defending politicians, so… no, just kidding, I'm not. But I will offer a more sympathetic explanation not from experience, just from my hindquarters.

If there were three different people in power who are all independently upset about a crime, I could imagine each of them figuring out what the suspect did in their jurisdiction. That’s to fight back personally as well as to have a story for the next town hall when someone includes the crime in a long list of places why $currentCity has gone down the tubes over $longPeriod

So then have these three separate cases because everyone felt disrespected and wants a billboard, “don’t mess with us“. Maybe it wasn't very relevant that the perp scraped a mailbox while peeling out of the scene of the crime, but is that a reason for the postmaster not to have his friends from the US postal inspection over? :)