Shipwreck explorer Joe Mazraani, 48, died during a deep-sea dive off the Massachusetts coast, as the investigation into his death continues.

P.H. Nargeolet, a French deep-sea explorer and Titanic expert, was one of the five men who died on the OceanGate implosion. His estate is now suing the company for wrongful death.

Sub Sea Systems said the helmet diving has over a 25 year track record of safe excursions with over three million people participating in the activity.