If you pull way back, and look at the people who created this moment, and the parade of witnesses for the prosecution—just their job titles, not their names or faces—you see the component pieces of civilization, the human architecture that actually creates the conditions for abstract notions like justice and mercy and safety.
The police officer who's seen thousands of bloody crime scenes in his life, and knows the first thing you have to do at the aftermath of a chaotic stabbing is secure the area and ask: Where's the bad guy? Which way did he go? What did he look like? The firemen who wait down the block until the policemen have secured the area, then rush in, rubber gloved and blue smocked, to save and comfort whoever they can. The canine unit that tracks the scent. The emergency room physician who swabs the survivor for evidence and, for a time, with the survivor's best interests in mind, withholds the information that her partner has been killed. The coroner who autopsies the deceased. The crime lab that processes the evidence. The detectives who track down the leads. The social worker who comforts the victims' families. The Metro bus driver who notices the suspect getting off his bus. The patrol officer who races over and arrests him. The state psychiatrists who treat the suspect. The attorneys who prepare his defense. The attorneys who prepare his prosecution. The judge. The bailiff. The jury.
It's taken all of them, and many more people, nearly two years to create this proceeding: A fair trial.
This should give you pause when people speak dismissively of due process, or of "legal technicalities"...of whether certain people deserve such consideration or not. A system of justice is foundational to civilization itself, and it is hard-won.
The people who are willing to so readily cast that aside for mere vengeance are a much greater threat to our civilization than any one murderer, rapist, or terrorist could ever be.