Wild guess: Ning did the shooting. First of all, she has no dialogue throughout the story, which is a clue itself. Lots of murder mysteries turn out to be done by a background character, someone who doesn’t appear to be relevant to the story. Secondly, in the two panels she appears in (Tues, Fri), her right hand is covered, perhaps due to some gun residue or some other reason. The other possibility is Jerry Lennox. How did he know Mr. Reeves was hurt?
Cue Sydney Sweeney on SNL.