I read the full post. It sounds like somebody trying to fake a message, and doing poorly. I mean - REALLY poorly. It sounds way too formal, too many complete sentences. Using the word vehicle, instead of car. Who does that, except a fed?

Also...he's worried about evidence, and then typing this incriminating message on Discord? The guy is supposed to be very intelligent. That doesn't make sense.

ROBINSON: “Why did I do it?”
ROOMMATE: “Yeah”
ROBINSON: “I had enough of his hatred. Some hate can’t be negotiated out. If I’m able to grab my rifle, I’ll have left no evidence. Going to attempt to retrieve it again. Hopefully they have moved on. I haven’t seen anything about them finding it.”
ROOMMATE: “How long have you been planning this?”
ROBINSON: “A bit over a week I believe. I can get close to it but there’s a squad car right by it. I think they already swept that spot but I don’t want to chance it.
I’m wishing I had circled back and grabbed it as soon as I got to my vehicle. I’m worried what my old man would do if I didn’t bring back grandpa’s rifle. Idk if it has a serial number but it wouldn’t trace to me. I worry about prints, I had to leave it in a bush when I changed outfits. Didn’t have the time or ability to bring it with. I might have to abandon it and hope they don’t find prints.”