Whoa! You sure you were a cop? I have been successfully arrested (and prosecuted!) for several misdemeanors, never committed in the presence of an officer.
I now doubt your backstory.
Yes I’m sure I’m a retired LEO. There are certain misdemeanor theft offenses where you can be arrested without the theft being witnessed by an officer. In this case, if it(the assault) wasn’t done in the officer’s presence, you would have to proceed by summons or warrant.