When watching the series Fringe (and any other police series for that matter), the police/FBI usually looses their suspect because he is running away and the police keep yelling "stop or I will shoot". The suspect escapes and the show can go on.
I understand that this is needed for the drama, but since they are consistently warning the suspects, I came to wonder whether there is a legal protocol behind that.
Are police/FBI/similar forces obligated to warn someone who is running away that they will shoot? Can they just shoot him in the back (or wherever they manage to aim) when they have the chance?
I am specifically talking about
- the case where the fugitive does not pose an immediate threat to the police (by shooting at them for instance) but they really need to stop him right away (possibly killing him in the process).
- the legal protocol for that exact situation (not any mistakes/accidents/... - I am not interested in linking this to any current events)
The question rose after watching US TV series but I would also be interested in the situation in France if possible (though US will be fine too for the sake of the show reality-checks).