[dcwusmc]

Could it be that they kinda KNEW who was in the car and wanted to put a scare into her father by jacking HER up? And maybe it sorta went awry? Or maybe it went exactly the way they wanted it to go. Wouldn't be the first time the drug warriors sent a "message" that way. Maybe he was supposed to be a snitch that was getting out of line. Or maybe he wasn't paying his "protection" money on time. Roscoe'd know that, probably. Maybe he's the DEA's bookkeeper for extorted funds.

[Zon]

I think the DEA agents didn't know who was in the car because they weren't paying close enough attention and just assumed it was Joey Villarreal driving. When they realized who they had shot they likely figured they couldn't very well say they made a mistake because they weren't paying attention to who was in the car. Thus they claim to know full well who was driving the car and that there shoot was justified because the driver was trying to run them down.