I think this person was making it up as he went along, hoping he could create enough of a smokescreen that the cops would say: "Yeah. OK, sure." And then, hopefully, they would melt away.
Magical thinking on the perps part, no planning, didn't have a alibi worth spit anyway. Just hoped he wouldn't get fingered for the crime, despite the fact that the parents (among others?) knew exactly who he was.
The cops lay low, saying there is "no evidence of foul play", giving the killer a false sense of security, while they scrutinize even the most infinitesimal move this guy makes, incriminating himself even further.
I think the murder occurred at the park. Why transport someone murdered elsewhere to an urban park? Much more logical to dispose of a body in an area far less frequented as long as there is the benefit of darkness, and time.
Additionally, it would very difficult to move a 140+ pound body (even with an accomplice) from the parking lot at that park to where Blaze was found. A plastic bin isn't going to help that process much.
Blaze was murdered where he was found. If this murder was at all premeditated, there were an abundance of rookie moves--which is fine. I don't want this person making any attempt to improve on his stupid mistakes.
(RIP Blaze. You did not deserve this. Millions of hearts bleed for you, and they want justice.)