I'm having a discussion with somebody online about a 911 dispatch call, the dispatcher uses the phrase, "Who did you shoot?" This seems like a perfectly normal phrase to me, and grammatically correct at that. They are asserting the phrase is not grammatically correct and due to that is causing confusion. They believe the phrase should be, "Whom did you shoot?"
I had never thought too much about the distinction, but after looking into the difference I can see why you might use "whom" here. "Whom" is replacing the object of the shooting in this case, if I understand correctly. At the same time, I've plugged both phrases into grammar analysis tools and neither gets marked as incorrect. The former phrase sounds more natural to me, probably because you just don't see "whom" used very often.
I've come here to settle the discussion, which phrase is actually grammatically correct, or are they both, why?