Quote:

… "The deputy of an off-duty sheriff" - what difference does it make if the sheriff was off- or on-duty?




Geez! That's why the interpretation that the sheriff was off-duty need not even be considered. There's such a thing as context in the English language.

All you have to do is read and understand the sentence. You don't have to set a bunch of hoops on fire so you can jump through them. Just read and understand the sentence.