The US Coast Guard has just begun its public inquiry into the Titan Submersible accident, and in the process has released a number of documents, including, critically footage from a remotely operated vehicle showing the wreckages on the ocean floor.
I believe this wreckage confirms that the failure began at the interface between the carbon fiber pressure hull and the forward titanium interface ring.
A great deal of composite debris has been pushed backwards into the rear hemisphere, while almost none is visible near the forward sphere.