The fact that Trump has not tweeted a message of sympathy and condemnation for the killing of Sicknick is the most disgusting thing he has ever done. He literally does not care his supporter beat a cop to death, despite his constant professions of support for the police.
That's because Trump has long been very hesitant to ever condemn any of his supporters in any meaningful way. His "support" for the police is paper-thin, like his support and loyalty for everything else except himself. It only exists so long as it serves his own interests.
Maybe it is for the better that Trump hasn't tweeted a message of "sympathy" - in such one he could easily go out a tangent and end up complaining that Sicknick made problems because was standing in the way of these "Very Fine People".