More danganronpa 2 (some predictions / the obviousness of the first case) - They set up "togami's?" death super quickly with "here's my past...no later" minutes before the blackout. The naegi clone was the one who set up the dining room, so he could easily set up the knife + paint under the table...which is where he was positioned pre-blackout.
edit: my god all these clues for this one really make it obvious there's 2 options, #1's "happening" failed murder plan reversal, or my prediction being right.