It makes sense to try to search at the Titanic wreckage. It's about the only place where it was possible for the submersible to get caught on something solid. (A drifting net was another possibility though). If somehow the vehicle was unable to surface but still able to move (though I can't imagine any plausible scenarios where that would happen), it would make sense for the crew to move it near the wreck, as the only landmark and thus the most likely subsurface location to be searched. And finally, the submersible was positioned at launch, and for the first 90+ minutes also guided, to descend as close to the wreck as the staff could manage. So if it lost power and sank, or imploded late in the descent, it would end up close to there.
It doesn't seem likely that a debris field would have been mentioned, if it were only Titanic debris with nothing to suggest otherwise. Unless something was badly garbled in communication. ("We've reached the debris field." "What?! You found a debris field??") So, it's looking likely we're all done here, except for whatever forensic examination of the failure can be managed.
