i did not follow this case closely, but i according to my own judgement, there is more than meets the eye. and i did not buy those newspaper to read, so what i write is all my own thinking. no biased according to race or whatever.
1. from the pic that the policeman was injured in his right hand, it is could highly be caused by a sharp object. ok. now the interesting point. who use the sharp object to attack him? very highly is the elder Tan. it couldn't be a knifefight, because if Tan loses (die) his knife should be in his hand or near him. but there is only 1 knife in the whole scene. (if i am right). therefore, i think it is the elder Tan takes a knife to attack him, the policeman use the hand to shield the knife, and at the same time, wrestle the knife away and use the knife on elder Tan in a confused state.
2. the policeman has no intention of killing elder Tan. therefore, realizing Tan is injured/dead, policeman panicked and drove the victim car. (i do not know the younger Tan is involved in the earlier fight or not. whether yes or no, it does not matter). when he reverse, he did not check is there anyone behind the car (u have to remember the policeman is panicking now), and quickly sped away WITHOUT knowing younger Tan is trapped underneath the car.
i going out for lunch now. will continue part 2.