The Transportation Safety Board is now expanding an investigation into the deadly sinking of the tugboat Ingenika near Kitimat, B.C., last month.
Mohan Raman, manager of Pacific region marine operations at the TSB, said an initial investigation has identified contributing factors in the sinking.
"We look at everything … and thankfully we have a survivor," he told CBC News.
Raman said the evidence so far justifies an escalation of the probe, not just to find a cause of the tragedy, but also to potentially identify new safety issues or advisories.
The MV Ingenika sank during an overnight storm on Feb. 11 while pulling a large barge in the Gardner Canal just south of Kitimat.
Crew members Troy Pearson and Charley Cragg were both killed in the incident. A third crew member, Zac Dolan, was rescued after washing ashore.
Widow's campaign to recover wreckage grows
Judy Carlick-Pearson, Pearson's widow, is continuing a campaign to salvage the ship.
"I really strongly feel that the answers are at the bottom of the sea," she said. "There may be nothing but there may be something and we got to keep pushing on that."
Carlick-Pearson's online petition to recover the tugboat has surpassed 10,000 signatures.
She said her young son already talks about a life on the sea. Carlick-Pearson believes any answers provided by the salvage would benefit all mariners and provide a step toward closure.
"It's going to be a livelong mission of mine and I can see it being a lifelong mission of my son's," she said. "We're not going to let up, we have no reason to let up, and we have nothing to lose at this point."
Listen: Judy Carlick-Pearson talks about her efforts
Coast Guard says recovery 'difficult and very dangerous'
The TSB's Raman said raising the wreckage may not be possible, or necessary.
"We don't have the authority to order anyone to raise it," he said.
"If we had that boat, it would help us just confirm or negate some of the things that we would consider."
Raman said the TSB website will include updates on the investigation, but he does not expect a final report on the sinking for at least eight months.
"So far efforts to locate the Ingenika have been unsuccessful." the Canadian Coast Guard said in a written statement. "The suspected depth of the vessel would make any attempts at recovery difficult and very dangerous."
The Canadian Hydrographic Service will survey the waters in an attempt to locate the wreckage and assess any navigation obstructions. The Coast Guard says there does not appear to be any environmental threat of pollution.
"Ultimately the owner of the tug is responsible for addressing any marine pollution and any attempts at recovery," the Coast Guard stated.