Transportation Safety Board of Canada investigators are boarding the grain ship where a worker died last weekend.
The TSB now says initial reports suggest the 41-year-old man fell to his death.
The ship "Tecumseh" left Thunder Bay after the accident and docked in Windsor Tuesday night.
The incident was initially considered a labour-related issue, but "at this point in time the Transportation Safety Board believes that [the incident] might be something of interest to advance marine transportation safety," senior investigator Stephane Chevalier said.
The TSB team wants to hear first-hand what happened by "interviewing the crew, looking at what happened" and reenacting "the sequence of events."
"We will also, if needed, take items away from the vessel that we can bring to our lab in Ottawa for ... further testing if it's required," he said.
Chevalier said the team will likely spend a few days with the ship in Windsor, however he noted a complete investigation could take 12 to 14 months.
The man who died hailed from the Greater Toronto Area, but his name has not been released.