Presume that similar to air incident investigations, there'll be a forensics investigation on the wreckage to formally determine the cause of the incident.
However, the difference between the two situations is that aircraft have fully documented designs and maintenance reports, whereas this craft appears to have been cobbled together with zip ties.
I'm trying to figure out if the person you replied to was asking because they thought you meant parts of the sub or the remains. In fact, I'm not even sure which you meant lol.