Polar Prince: Support ship docks at Canadian harbour as rescue operations wind down

The Polar Prince has returned to shore in Canada where it faces an investigation into its role in the catastrophic implosion of the Titan submersible.

Flags on board the vessel were at half-mast as it docked in St John's, Newfoundland, on Saturday.

Another boat was seen in the harbour towing the Titan's launch platform.

The Titan was on a dive to the wreck of the Titanic when it broke apart, killing all five people on board.

The Polar Prince towed the submersible out to the area in the North Atlantic where the Titanic sank, about 400 miles from St John's.

It carried members of the support team and some family members of the victims, and was involved in the search for the vessel once it lost contact about one hour and 45 minutes into its dive on Sunday.

Parts of the submersible were found on Thursday, approximately 1,600ft (487m) from the bow of the Titanic wreck.

Canada announced on Friday that it was launching a safety investigation. Other countries' government agencies may join in, but it is unclear at this stage which will lead the investigation.

As well as the role of the Polar Prince, experts say officials will also look at the materials used to make the sub's outer walls.

Since news of the accident broke, industry experts have come out to say that they had raised questions about safety practises at OceanGate, the company that owned the Titan, and whose CEO Stockon Rush was on board at the time of the accident.

Emails seen by the BBC showed Mr Rush dismissing concerns from one expert as "baseless cries".

Also on board the Titan were Shahzada and Suleman Dawood, Hamish Harding, and Paul-Henry Nargeolet.