Killer Whale. They have been observed killing Great Whites.
The thing that ate this shark (or the chunk of the shark that had the recording device) grabbed it and dove fast and steep to a depth of nearly 590 meters, or about 1,900 feet.
Killer Whales only dive to about 30 meters, apparently, which makes sense. They don't NEED to go real deep; most of their food is going to be at shallower depths, and that's what their bodies are set up to withstand.
A squid, on the other hand, is virtually oblivious to the pressure of the ocean depths. And Great Whites can also dive very deep. The only thing that makes me think it wasn't a bigger Great White that ate it, is that sharks don't grab food and dive to eat it. They chow down in place.
My question -- are squids warm-blooded enough to be about 73 degrees at that depth? Because that's what the data indicated, that this critter, whatever ate the shark, had that kind of body temp.
Very doubtful that it was a Killer Whale, though. They don't dive that deep.