1) Sounds like a drug ripoff gone bad, so of course the cops are going to pile as many charges as possible on the ‘victims.’
2) Even in the United States, (with the exception of Texas, and only at night,) shooting at someone who is fleeing is a felony.
Indeed. It's one of the few common-sensical laws that Texas has that is superior to many states. Personally, I think it is silly for a citizen to not be able to stop a fleeing criminal, as there is no way to know if they are just going for backup, or to return at the time of their choosing when one might not be prepared to defend against them. Just because a criminal is leaving the scene at the moment, does not mean they do not intend to return to do you harm.
What if that someone is running from you and firing at the same time?
There should be a Fleeing Felon statute, making it a felony to flee law enforcement, and permitting shooting of felons in the act of a felony. Clean out the gene pool some.