As long as there is an exotic pet trade, there will be a constant source for new lost or dumped anacondas and pythons roaming free.
It seems more likely that it was an anaconda, since they hunt in the water and kill much as alligators do, by drowning their victims; they kill crocodiles and will eat anything. Pythons prefer dry land and to eat birds and mammals. Not that it matters much to that alligator.
I think it may be too late to stop now that they are breeding in the wild.
You have to wonder what geniuses allowed it in the first place.