Total speculation on my part, but what I think may have happened is:
-This was a drug deal gone bad.
-Someone else outside of Hernandez’ crew (on the dealer side) shot the guy.
-They all panicked and didn’t want the drug deal part to get out (because of Hernandez’s employment).
-They left the body (thinking they couldn’t be linked to it since they didn’t touch/kill him).
-They went back to the house and did all this other stuff (phone/camera smashing, hiring the cleaning crew) to hide the fact they were there. The phones probably have references to the deal, perhaps what happened after, and the camera obviously shows them returning just after the murder.
-They initially refused to cooperate out of fear they’d be killed next.
Who knows if this is the case, but if so it is the BEST CASE SCENARIO for Hernandez at this point and he had better say it and say it SOON. It’s certainly better than being linked to murder.
This all makes more sense to me than Hernandez and his friends taking the guy (who happens to be his fiancé’s sister’s boyfriend) to an isolated industrial park and killing him. They were just out partying with the guy. Think about it: it’s early morning and they’re leaving the bar. Maybe they decide they’d like to pick up some marijuana or (more likely) cocaine and continue the party back at Hernandez’s house. So they call their dealer (or maybe one they met while out) and have him meet them at the industrial park (convenient since it’s close to his house and the perfect place for a late night drug deal because no one is around). Something goes horribly wrong and their friend winds up dead (either the dealer tries to rob them, someone mouths off, whatever).