Efforts are now underway to recover a vessel and the six people presumed drowned off the coast of Richmond.

Richmond RCMP said four men and two women remain unaccounted for and are presumed drowned after a charter boat sank off the coast of Richmond, in the Roberts Bank area, on Sunday.

Four people were rescued following the capsizing.

Nearby vessels raced to the commercial charter boat, but rescuers say that by the time they arrived, only four people were found alive.

Richmond RCMP said the recovery of the vessel is complex because the water where the vessel sank is deep.

“So where the boat sank, they’re thinking the water there is approximately 150 to 180 meters deep, which is really deep,” Cpl. Frank Bryson with Richmond RCMP said.

“So they’re going to need some specialized equipment — underwater drones and things like that — to go down. So they’re looking at a time when the weather is cooperating and they can get down and utilize some of those tools.”

Bryson added that for those who are presumed drowned, next of kin notifications still need to be completed.

He did not provide any information on whether the people on the boat were locals or tourists.

The Transportation Safety Board confirmed on Tuesday that it is investigating what happened.