"Little boys" who place 3 well aimed shots on a police car windshield, you don't need a big dick to shoot accurately and kill people. If a cop was killed, he might have been in that seat. Just guessing, but the cop(s) might have stopped the teenagers car, teenagers jump out every door all at once with guns blazing surprising the cops then drive off, police car chases them and crashes into them at high speed then cops blaze away at dazed survivors not taking any more chances.
When shooting at cops, all bets are off.