Just because 2 options are presented doesn’t mean there aren’t other possibilities.
That said, I’m inclined to believe #2 or at least some variant of it.
Question: If #1 were really true and his parents believe it’s a botched robbery, why would they want to impede the investigation. If they are correct, an investigation would
A. find the killer
B. clear his name
C. remove the controversy
Motives for opposing an investigation :
A. They are afraid of what might turn up. They are afraid of the truth coming out
B. They are being threatened.
C. They are being paid off.
These are not mutually exclusive motives. It may be that all 3 are true.
My brother was recently mugged. They knocked him out and stole his wallet and phone.
The police told him that there wasn’t going to be an arrest or investigation because it happens too frequently and it is too hard to catch the perps. IOW just another white victim.