Calgary police are probing the death of a man who died following an altercation with border officers as they were trying to deport him.

Police, who have not publicly identified the man, said it will be months before full details can be released about the man's death.

But documents from the Immigration and Refugee Board of Canada Immigration Division identify the man as a Nigerian citizen who had been engaged in a lengthy battle to stay in Canada.

The Canada Border Services Agency (CBSA) is not naming the man until his next of kin have been notified.

An autopsy performed Wednesday did not confirm a cause or manner of death. Further testing can take up to six months, said Staff Sgt. Colin Chisholm with Calgary Police Service's homicide unit.

"We will do a complete, thorough investigation. These investigations take time, and like any investigation, especially in this investigation, we're going to wait for official autopsy results to come back," Chisholm told reporters at a news conference Thursday.

The man was on board a KLM flight destined for Amsterdam when he had an altercation with two CBSA officers who were trying to remove him from the country.

The altercation took place prior to takeoff from Calgary. The plane was forced to return to the gate, where the CPS airport unit was called to the scene.

Officers found the 49-year-old man in medical distress. He was rushed to hospital, where he was pronounced dead.

According to police, the altercation with the border officers took place around 3 p.m. He was officially declared dead an hour and a half later.

The two CBSA officers were taken to hospital with minor injuries. They have since been released.

He first arrived in Canada in 2005

A detention hearing transcript from the Immigration and Refugee Board of Canada Immigration Division on July 26 said he was detained on the grounds that he likely wouldn't appear voluntarily for his flight, due to comments he made saying he wouldn't allow himself to be removed from Canada.

He first arrived in Canada in 2005, making a refugee claim at Fort Erie. The claim was abandoned, and then reopened, and then refused by the board in 2008.

He filed two humanitarian and compassionate applications between 2009 and 2013, but both applications were denied.

In 2014, he applied for leave and judicial review of that decision, but that was denied as well.

The immigration board undertook a pre-removal risk assessment on him in 2015, to study if he would be in danger or at risk of persecution in Nigeria, and the assessment found he was not at risk.

"[He] is adamant that he will face harm if he is returned to Nigeria and he has consistently told officers that he will not return to Nigeria on his own and that he would only go back if he is forced to," the transcript reads.

CBSA warned removal could be violent

An interview between the man and the High Commission of Nigeria recounted in the transcript noted that "[his] removal would likely be violent and advised CBSA to take caution."

"This is a life and death issue," he said in the hearing, according to the transcript. "I told the officer if you are asking … 'You are sending me to my death.' It's like you are asking me to drive into a ditch … very dangerous for me."

He said he worked full-time in Canada and would continue to show up to CBSA hearings.

"I'm not asking for money, I'm not asking for housing, I'm not asking for medical help, all I'm asking for is please, your honour, save my life."

However, the immigration officer speaking at the hearing said in the past, he had told officers that, "I understand that you have concerns that I will cause an issue that will disrupt my removal. You are absolutely correct about this. I will cause a big issue and will not go."

He had no family in Canada and few friends, an immigration officer said in the hearing.

On Wednesday, federal Public Safety Minister Ralph Goodale described the circumstances of the man's removal as a "normal removal from the country when a person has been determined to be inadmissible."

Police are still interviewing witnesses and are looking to speak to "everybody and anybody" who was on the flight or who may have seen something. They are also working with authorities in the Netherlands to conduct interviews with the flight's passengers.

Chisholm said based on the information they have now, he does not anticipate charges will be laid in the case.

Anyone with information on this incident is asked to contact Calgary police at 403-266-1234 or Crime Stoppers anonymously.