Since the defendant killed an elected official and tried to kill a city employee while they were performing their official duties he should have been charged with one count attempted murder in the first degree and one count of murder in the first degree. Murder two and attempted murder two would not be appropriate charges.
At no point do any of the characters mention that if the FBI didn't conduct the search of Rubin's apartment, the police would have found his gun during their search and collected the same fingerprint and ballistic evidence that the FBI found.
In the courtroom, when the surviving shooting victim identifies the defendant as the shooter, he describes him as "the man sitting over there in the gray suit". However the defendant's jacket is clearly black.