The Conservative government has launched an inquiry into the investigation of the Air India bombing, Prime Minister Stephen Harper announced Monday.

• INDEPTH: Air India

Prime Minister Stephen Harper in the House of Commons on Monday. (CBC)

Harper said his government decided on the terms of reference for the inquiry after retired Supreme Court Judge John Major, who will lead the probe, consulted with family members of some of the victims.

"It is about finding answers to several key questions about the worst mass murder in Canadian history," Harper said in the House of Commons.

The government hopes the investigation brings "a measure of closure to those who still grieve for their loved ones," he said.

Harper has long supported a full judicial inquiry into the investigation and prosecution in the bomb, which killed 329 people when it blew up aboard Air India Flight 182 when as it was travelling off the coast of Ireland in June 1985.

Weeks after winning the Jan. 23 parliamentary election, Harper asked Major to meet with the victims' families.

Flight 182 originated in Vancouver, stopped in Toronto and was en route to India via London when the bomb went off.

A second, linked bomb – which was planted in a suitcase on another Air India flight in the same day – killed two baggage handlers when it exploded at Japan's Narita airport.

• FROM MARCH 16, 2005: Malik, Bagri not guilty in Air India bombings

The call for an inquiry became more heated when two men who had been charged in the bombings were set free after a lengthy trial found them not guilty.

Two B.C. men – Ripudaman Singh Malik of Vancouver and Ajaib Singh Bagri of Kamloops – were acquitted in March 2005, after a judge ruled that the Crown's case against them was too weak.

Only one person has ever been convicted in the attacks – Inderjit Singh Reyat. He was sentenced to five years in 2003 after being convicted of manslaughter and with assisting in the construction of the bomb.

Reyat had a court appearance Monday for allegedly lying at the Air India trial. He appeared in a B.C. courtroom via videolink on charges he lied during Malik and Bagri's trial.

In November 2005, the then-Liberal government accepted Bob Rae's recommendation to hold a focused inquiry into the Air India investigation and prosecution. The former Ontario premier, now a Liberal leadership candidate, had been asked to advise the government on the issue.

Rae recommended the inquiry focus on:

• Whether the assessment that the bombings were linked to Sikh militants – who wished to create an independent homeland – was adequate in light of available information.
• Whether the RCMP and the Canadian Security Intelligence Service co-operated adequately in the investigation.
• The relationship between intelligence gathered and evidence presented at trial.
• Any breaches of airport security and if those issues have been addressed.