TORONTO -- Watch “Flight 752” on Saturday, March 27 at 7 p.m. ET

TORONTO - 176.

That’s the number most important in this story. 176 mothers, fathers, brothers, sisters, sons, and daughters killed because they were shot out of the sky by a missile launched by Iran’s military in January 2020. Fifty-five Canadian citizens were on board, and 30 permanent residents. The flight on Ukraine International Airlines was heading from Iran to Kyiv, but most were travelling on to Canada.

More than a year after Flight 752, there are few answers as to why it happened, or proof that it was, as Iran claims, “human error” and a misaligned missile.

Iran recently released its investigation report, but the government won’t discuss the military’s role in the shootdown, even though they claim disciplinary action has been taken against members of the Islamic Revolutionary Guard, who they claim, mistook the plane for a “hostile target.” Because of inconsistencies, Agnes Callamard, UN Special Rapporteur on extrajudicial executions, is among the global experts questioning “whether the downing of Flight PS752 was intentional.”

W5 reached out to Iran’s Foreign Minister Javed Zarif for comment on this story, but Iran did not respond.

Meanwhile, the Canadian federal government rejected Iran’s report saying it lacked “hard facts or evidence.”

Ewen Tasker, who travelled to the crash site for Canada’s Transportation Safety Board, describes it as “incomplete.” The TSB was denied an active role in the investigation, and was only given observer status. Ralph Goodale, the Prime Minister’s Special Advisor on this file, called the report “shambolic” and “insulting” to loved ones.

So where does that leave Canada?

Former UN war crimes prosecutor, Payam Akhavan, says Canada has options.

“The point is to have a proper investigation,” Akhavan says. “And it's not going to happen with Iran unless they are put under considerable pressure.“

He says Iran has been given the opportunity to be transparent but has failed, and so now the international community must step in. Akhavan says Canada could take Iran to the International Court of Justice (ICJ).

“What have we got to lose by trying?” he asks.

He says dragging the Islamic Republic of Iran before the court in the Hague will force them to put evidence in front of 15 judges and create pressure for them to identify those responsible.

This has happened before.

In an ironic twist, it was Iran that took the U.S. to the ICJ after Flight IR655 was shot down by an American navy warship in 1988. Two hundred and ninety people were on board the flight bound for Dubai from Iran. Akhavan points out that Iran later settled with the United States and used the case as a bargaining chip for better compensation.

Flight MH17, on Malaysia Airlines, was also struck down by a missile in 2014. Two hundred and ninety eight people died in that crash, the highest number of civilian casualties in a missile shootdown. It happened in Eastern Ukraine, in Russian-controlled territory. Russia has denied any responsibility. Australia, which had 38 citizens on board, petitioned the UN security council for an independent investigation. UN resolution 2166 opened the door to that probe, where investigators were able to figure out how the attack was carried out and who was allegedly behind it. The case is currently before the District Court of the Hague where three Russians and a Ukrainian are facing murder charges for their alleged roles in firing a missile at the plane. The Netherlands has also taken Russia to task at the European Court of Human Rights.

Ralph Goodale, appointed to provide Canada’s ongoing response to Flight 752, tells W5 that Iran needs to not only admit what they did, but why they did it. If they don’t, Canada can appeal to the International Civil Aviation Organization or ICAO to try and understand the technical reasons why this happened. If that fails, he agrees Canada can then take this to the International Court of Justice for a criminal investigation.

“All of these methods of recourse remain open and available, and we will pursue them one by one by one as required to get the truth,” Goodale says.

Canada could also impose sanctions on Iran with legislative authority under the Criminal Code, the Special Measures Act and Magnitsky legislation.

“Either sanctions against the state or sanctions against the terrorist entities or sanctions against individuals,” says Goodale.

Friends and families of the victims of Flight 752 have filed a petition in the House of Commons, to appeal to the UN for an independent investigation. Goodale is asking for their patience in a very complex process.

“If you make a misstep along the way, then you can, for example, deny yourself ultimately the jurisdiction to get into the International Court of Justice so that you've got to follow this process in a careful, meticulous way,” he says.

Akhavan says when an international court case is launched, evidence often starts to surface and people come out of the woodwork.

“Once people realize that there is a court case, they may be willing to take a risk they otherwise would not,” he says.

Still, he concedes any international attempt at justice is an uphill battle.

“My whole career has been to use very weak international mechanisms to uphold international law… which nine times out of 10 ends up in frustration and anger. And then one in 10 times you actually achieve something and say, ‘it’s still worth it,’” the former UN prosecutor says. “Maybe I'm naive, idealist or just foolish, but I don't want to give up. Truth matters, justice matters.”