I don't think it was caught...if the 1 ton weight is correct, then that croc was a captive crock and was fed a lot of chicken and beef. I think it may have escaped or was being moved...
In order for a croc in the wild to obtain that type of weight, he'd be feeding on some very large prey and regularly...like cattle, humans (dead or alive), or large fish. And since they are ambush predators...the former rather than the latter would be the best choice.