Calgary police say they are in the early stages of their investigation into the death of a man who being deported to Amsterdam from Canada.
The man died following an altercation with two Canada Border Services Agency officers on a Tuesday flight departing from Calgary.
Police say they responded to a plane that had returned to the gate after the altercation.
Both the agency and police say the man was in medical distress and was taken to hospital, where he was later pronounced dead.
Police say an autopsy has been completed, but they are still trying to determine the cause and manner of death.
They say the man's name will not be released until his family is notified.
Police add that the border services officers were also taken to hospital, where they were treated for minor injuries.
Investigators are still speaking to witnesses to determine what happened before the man went into medical distress.
"This is being investigated as an in-custody death," said Staff Sgt. Colin Chisholm. "To protect the integrity of the investigation and prevent any influence on the recollection of witnesses, there is limited information we can share at this time."
They ask anyone who witnessed the altercation to call police.