how do they know?

Someone sent me an email photo story about dissecting a croc who apparently had devoured someone....

It was pretty gross... they had the croc tied and flipped belly up... and I have no idea if they had killed it first or just slit its belly open while it was alive... and on the inside, they pulled out two arms (fingers all the way up to the shoulders) and two legs (toes up to the thighs) and there was a head peeking inside the intestines.

Ugly sight... sad sight... but also interesting at the same time.........

But what makes me really curious is that... how do they know?

How do they know that it was THAT croc? Did they catch and cut up a few large crocs to find out? Did they stick around to find out which croc wasn't hunting (therefore would seem suspicious cuz they don't do any hunting which would of course take a long time since crocs are cold-blooded and therefore have slow metabolism rates enabling them to go without food for an uber long time)? I don't think there would be only ONE croc in the river because they're not that all solitary creatures and I'm pretty sure they didn't tag the poor soul who was devoured....

Cuz as far as I remember, crocs like to drag their victims and drown them... and the occasional 'death roll' if it's too chunky/large for them.... and most of the accidents like these... are reported as attacks... and not swallowed.... where the victims are mostly maimed... and mauled....

Okay you know what this is getting icky and depressing and just plain yeurrghhhh... I'll stop now....