Back in the old days, if you disputed the charge/ticket and showed up for court and the officer neglected to, the charges would be dropped. I’m not sure if that still applies. If memory serves, they now have an officer that does nothing but sit in court all day for such events.
One of the tickets I got out of was due to the failure of the ticketing officer to show up. However, I had to specifically oppose the prosecuting attorney’s motion for extension and ask for a dismissal of the charges (it felt really cool).
As for a sitting officer, I’ve never heard of that. The present officer has to be a witness to the infraction, or there is no case.