If it isn't Naz it's either Duane Reade, the hearse driver, who I hope comes up through surveillance footage review, or potenitally the funeral guy who was all pissed. Or potentially her step dad if there's maybe some weird sex stuff going on between them.
Ideally all this should come up before someone is charged, along with blood evidence on Naz or in Andrea's shower, or evidence of him changing / something to prevent himself to get caked in blood, which is why this investigation from the police side is fucked, along with breaking the chain of evidence. The police comepletely missing the open back gate is also completly fucked, as it opens the door to virtually anyone being the perp. Not nearly enough background police work was done to determine if it was someone who knew her that did this, given there is eyewitness testimony that Naz left through the front door.
Most likely Naz will be charged with grand theft, with his own father's cooperation, which is a nail in the coffin, so to speak, for the prosecution, but sadly it seems like his father isn't smart enough to understand that.
All of this should make for a relatively solid defense case, which I hope is covered over the next several episodes. Otherwise, yeah, HBO writers can get fucked.
Ultimately if it is revealed that Naz is in fact innocent but is still convicted, this feels like it may end up turning out to be a social commentary on our criminal justice system, which is honestly fine by me. Depressing, but probably better than a happy ending. I would think it is at least a very appealable case based on the chain of evidence being broken alone, but it means an innocent man locked up for years because of over eager police and prosecutors to work quickly to get a conviction for the murder of a young white person living in an affluent part of NYC. Which does seem like a fairly realistic scenario