Devastated family members of the victims of the Titan submersible tragedy are aboard the ship which lost contact with the vessel, as investigations continue.
Earlier today it was reported crew aboard the Polar Prince have been banned from leaving the vessel amid a probe into the tragedy.
The ship was among four vessels which returned to St John's in Newfoundland today, following the tragic deaths of Brit Hamish Harding, father and son Shahzada and Suleman Dawood, Stockton Rush, and Paul-Henri Nargeolet.
Safety investigators have begun talking to those who were on the ship towing the doomed submersible Titan last week, amid fears it may take two years before it is known for certain what happened 3,400ft below the surface of the Atlantic.
Kathy Fox, chair of the Transportation Safety Board of Canada (TSB), confirmed some family members were also aboard the ship.
She told a press conference: “This morning the Transportation Safety Board of Canada, or TSB, has started the safety investigation into a marine occurrence with fatalities involving the Canadian vessel Polar Prince.
"There are family members on the ship. I'm not going to share the content of any interviews because, just like voice recordings, the content of witness interviews are protected under Canadian law.
"Anybody can imagine that it's difficult, the circumstances they have been under for the last few days and we have to understand that's going to affect... particularly the families who have lost loved ones.
"At the time of the occurrence, the vessel was involved with the operation of a submersible known as the Titan which has been reported to have suffered a catastrophic implosion leading to the presumed deaths of the five people on board.
"This morning, TSB investigators boarded the Polar Prince to examine and document the vessel, to collect information from the vessel's voyage data recorder and other vessel systems that contain useful information.
"We have also begun conducting interviews with the people aboard the vessel.
"At this point we are not in a position to provide specific details about the occurrence or about the investigation that are not already in the public domain.”
She added the TSB is aiming to compete its investigation faster than the usual time frame as the world is after answers.
She said: "Typically our investigations take 18 months to two years.
"We obviously try to do them quicker, because we know that everybody wants answers - particularly the family, the public etc.
"We need to take the time with respect to how far we will go, that remains to be seen as we gather information.
“So it's still too early to tell."