I agree. Once they are 18 it’s on them.
In this case, however, I would not be surprised to learn the parents were involved.
18, 20, or whatever age the punk might be there’s another element in this case that put’s the parents at huge risk/exposure.
The punk reportedly had no ID on him but was quickly identified by the rifle which had been purchased locally , by the dad, in 2013. The shooting happened after normal bizness hours but ATF would not let that slow down a trace. They would wake up the dealer and check his records to the buyer.
The parents claim the punk said he was going to take the gun to the range. Doesn’t matter if he lied because the dad still owns the gun. No different that if the punk killed somebody while driving dad’s car.
Because a person died, most likely by a bullet from dad’s gun, there is some heckuva liability on the parent’s part.
As a side note it might get interesting that maybe there were two shooters? The parents would have an interest in proving their own punk didn’t fire the kill shot on Corey?