If there were no Trayvon Martin prints on it, it would be inappropriate to focus too much on it even if it were a professionally made slim jim (which used to be available at auto supplies) given the number of burglers running around. A wide number of potential owners of the tool makes it a stretch to automatically link it to Trayvon.
Even if I suspect it was his and was probably fabricated from something.
I really think the explanation for his behavior is simpler than that. He was out skulking around and looking in people’s windows at night. If anybody knew where he lived, they’d tip off the authorities, or his dad, and he’d be in trouble. So when he saw that Z had spotted him at home and now knew where he lived, he decided to eliminate the witness. Yes, it’s an over the top reaction to avoid a relatively minor consequence, but sociopaths do that kind of thing all the time.