Glad the one scumbag is dead- if I had to guess, it was one doper/gang group hitting another, and getting skanked.
It will all come out in the house.
In NM, a perp has to have part of his body inside your house before you can legally shoot him. I can't imagine this guy getting a free pass to kill someone who is in a field. You many be right about it being drug/gang related. It doesn't exactly seem like it was a father, son event. I also can't imagine 5-6 guys armed with assault rifles dropping their guns and running. That doesn't compute.
But this was in Texas, which is somewhat more good guy friendly and bad guy hostile.