TORONTO -- Families across the country grieving the loss of loved ones after 57 Canadians were killed in a plane crash in Iran may never have the chance to seek justice in their deaths, according to an aviation attorney.

鈥淲hen you have a missile that attacks a civil airliner, it鈥檚 a heinous act of injustice and it鈥檚 something that our international treaties are literally not prepared to answer for families,鈥 aviation attorney Alisa Brodkowitz told 麻豆影视 Channel on Thursday.

Prime Minister Justin Trudeau said intelligence from multiple sources indicates that the Ukraine Airlines jet carrying 176 people was shot down by an Iranian missile, but that the strike 鈥渕ay well have been unintentional.鈥

鈥淭he families of the victims and all Canadians want answers. I want answers. That means closure, transparency, accountability and justice,鈥 Trudeau said Thursday.

But getting closure is far from certain, according to Brodkowitz, who cited the 2014 crash of Malaysia Airlines Flight 17 shot down by a Russian-made missile over eastern Ukraine.

鈥淪o what we saw in MH17 is that people, individuals, can鈥檛 just sue a government. You have governments that can sue other governments, for instance in the Hague at the International Court of Justice,鈥 she told 麻豆影视 Channel on Thursday.

鈥淏ut there is no legal recourse. There is no justice for victims of these families because the treaties don鈥檛 really have any teeth.鈥

Last summer, international prosecutors in the Netherlands announced murder charges against four people, including three Russians with military backgrounds, in connection with the MH17 crash. Russia called those charges unfounded and is not expected to extradite any of the accused men for the trial later this spring.

Families of the MH17 victims also filed lawsuits against Malaysia Airlines, accusing the airline of negligence and breach of contract for flying a passenger plane through a known conflict zone. The airline reportedly settled damages claims with families of 165 victims.

Iran is leading the investigation into the crash with involvement from Ukraine. Iran has granted Canada access to the crash site, the Transportation Safety Board of Canada confirmed Thursday, and Canada is currently making arrangements to travel to the site outside Tehran.

The investigation鈥檚 structure follows international guidelines. According to which sets standards around aircraft fatality investigations, 鈥渢he state where the accident occurs will lead the accident investigation.鈥 The airline鈥檚 country of origin 鈥 Ukraine, in this case 鈥 is also considered a main party. Countries like Canada that have lost citizens in a crash to the lead investigator to have access to the crash. 

But if intelligence sources are correct that an Iranian land-to-air missile shot down the plane, Iran鈥檚 role leading the probe could be a clear conflict of interest, Brodkowitz said.

International law also makes it clear that member states will not shoot down a civilian aircraft.

鈥淏ut what happens when you do? The law does not have any teeth. So that definitely complicates things,鈥 she said.

BLACK BOXES WON鈥橳 LEAVE IRAN

Iran said the plane鈥檚 black boxes, which could help investigators determine the cause of the crash, will not be allowed out of the country. But Trudeau said Iran has agreed to allow Ukrainian investigators to access the boxes.

鈥淭hey have a duty to preserve all evidence,鈥 Brodkowitz said. 鈥淪o they must do that. And then in respect to black boxes, they have a duty to get those black boxes to a place, a country and authority, that can read them and disseminate that information.鈥

Ukraine鈥檚 involvement in the probe is 鈥渁 good thing,鈥 Brodkowitz said, because of its past experience with the MH17 crash.

鈥淯kraine has experience in what happens when a surface-to-air missile shoots down an aircraft,鈥 she said.

Ukraine Airlines flight PS752 crashed early Wednesday morning near Tehran shortly after taking off. The crash came just hours after Iran fired multiple missiles at a U.S. airbase in Iraq in a clear show of retaliation over the killing of a top Iranian general.

U.S. President Donald Trump said he ordered the airstrike that killed Gen. Qasem Soleimani because he was planning an 鈥渋mminent鈥 attack on Americans. The death of Soleimani, who was widely revered in Iran, triggered an outpouring of mourning in Iran. At least fifty-six people were trampled to death as thousands flooded the streets during his funeral procession earlier this week.

With files from CTVNews.ca鈥檚 Ryan Flanagan and Ben Cousins