Mysterious shark deaths do not necessarily indicate the presence of a massive, unknown marine predator. There are other, more mundane explanations. (Artwork by Thomas Finley)
As was expected, it seems that the shark's predator has been identified as a larger shark. So much for all of the premature and wild speculation. Thanks to cryptozoological researcher Dale Drinnon, who has refrained from any sort of irregular speculation towards this case as a proper investigator of unverified animals should, for bringing this to my attention.