I'll second the need for a review board, but an important component of that board is that citizens need to be able to make complaints without fear of reprisal from the police, which probably requires some sort of mechanism for anonymous complaints.
Still don't understand what was wrong with sniping the hostage-taker, though. So what if he was on the phone with a negotiator? It's not a game, that doesn't mean he's "on safe" or something. He still took hostages!
@Matthew - That's funny. It's not like he was "accused" of hostage taking, or "allegedly" a hostage taker. He was currently, right then, in the act of threatening peoples lives!