Good morning.

Monday marked 40 years since Air India 182 exploded over the coast of Ireland, killing all 329 on board, most of them Canadians.

It remains one of the worst acts of terrorism in the world, but it is also a uniquely Canadian outrage. I hesitate to use the word tragedy as that word suggests something horrible and unavoidable.

The downing of Air India was not unavoidable. In fact, while reviewing the timeline of events starting immediately after the disaster, it’s clear the bombing was, as retired Supreme Court Justice John Major concluded after a years-long inquiry, an act of mass murder. And it’s one that, due to shocking bungling, has never gone answered.

Aside from an obligation for Canadians to spare a thought for the hundreds and hundreds of damaged lives the bombing cost, the anniversary also offers a reminder that the case is and should remain open.

The explosives were placed in suitcases loaded onto planes leaving Vancouver on June 22, 1985. Police blamed the plot on Sikh extremists agitating for a separate homeland carved out of India.

One suitcase blew up as it was being transferred inside Japan’s Narita airport from a Canadian flight to an Air India plane, killing two baggage handlers.

Air India Flight 182, en route from Montreal to London and then on to Delhi and Mumbai, blew up an hour later.

It would be 15 years before anyone stood trial for first-degree murder.

RCMP raided the Vancouver-area home of Talwinder Singh Parmar and laid weapons charges, but those were dropped. Mr. Parmar was later killed in a shootout with Indian police and is believed to have been the mastermind behind the Air India bombings.

Inderjit Singh Reyat is the only person to have ever served jail time in connection with the bombings.

In May 1991, he was convicted of manslaughter and possession of explosives and sentenced to 10 years for building the bomb that exploded at Narita. He then pleaded guilty in 2003 to manslaughter, admitting he acquired the materials to make the bomb that destroyed Air India Flight 182. Then in 2010, he was given a nine-year sentence for perjury for lying at the trial of the two men who were eventually tried for the Flight 182 bombing.

In 2000, Ajaib Singh Bagri, a Kamloops millworker, and businessman Ripudaman Singh Malik were charged with 331 counts of first-degree murder.

But the Crown failed to prove its case and the two were acquitted in 2005. After hearing more than 200 days of testimony, Justice Ian Josephson concluded the case was built on witnesses with questionable credibility and with motives to lie about private conversations.

A public inquiry, called in 2006 and conducted by retired Supreme Court justice John Major, heard shocking testimony, including from Ontario’s former lieutenant-governor, who disclosed that Ottawa knew about a terrorist threat to the airline days before the 1985 bombing.

The inquiry also heard that RCMP had a telex, dated just weeks before the bombing, from Air India authorities forecasting a bomb hidden in luggage that very month. It did not share the information with the Canadian Security Intelligence Service (CSIS).

Families of the Air India 182 bombing victims have long agitated for Canada to do a better job of remembering the attack and the injustice that still remains.

But the 40th anniversary comes after relations between India and Canada crumbled after then-prime minister Justin Trudeau revealed his government had received credible intelligence that agents of the Indian government may have been behind the murder of Hardeep Singh Nijjar.

Nijjar was a prominent leader in the B.C. Sikh community and had been active in a renewed campaign for an independent Khalistan.

Supporters of that campaign convinced Surrey-area MP Sukh Dhaliwal to sponsor a parliamentary petition calling on Ottawa to order a fresh inquiry into Air India. Petition proponents want the inquiry to investigate the widely discredited theory that agents of India were behind the bombing of Flight 182.

The anniversary provides a good time to push back against such revisionism and remember there is still work to be done.

This is the weekly British Columbia newsletter written by B.C. Editor Wendy Cox. If you’re reading this on the web, or it was forwarded to you from someone else, you can sign up for it and all Globe newsletters here.