By Chris Summers
Two Canadian Sikhs have been acquitted of blowing up an Air India jumbo jet over the Atlantic in 1985. But the case, which reached its verdict in Canada on Wednesday, has led to renewed calls for police in London to solve the murder of a British Sikh newspaper editor.
Tarsem Singh Purewal may have been a witness in the Air India trial if he had not been gunned down on a west London street one winter's evening in January 1995.
6 Jun 1984: Indian troops invade Golden Temple in Amritsar to flush out Sikh separatists
31 Oct 1984: India's prime minister Indira Gandhi is assassinated by her Sikh bodyguards. In the ethnic riots which follow 3,000 Sikhs are killed.
23 Jun 1985: A bomb blows up Air India Flight 182 as it flies from Montreal to London. 329 people are killed.
24 Jan 1995: Tarsem Singh Purewal shot dead in Southall, west London.
16 Mar 2005: Ripudaman Singh Malik and Ajaib Singh Bagri acquitted of Air India bombing.
Mr Purewal, 60, was editor of Britain's selling Punjabi-language weekly, Des Pardes, and was killed as he shut up his office in Southall.
Although it happened on a busy street, few people claimed to have seen anything and the killing had all the hallmarks of a professional hit.
A decade later, the case remains unsolved, as does the murder in Vancouver, Canada, of Mr Purewal's close friend and fellow newspaperman Tara Singh Hayer.
Mr Hayer, who was already in a wheelchair after another shooting, was murdered in 1998.
Many fellow journalists and members of the Sikh community believe the pair were killed because they knew too much about the Air India bomb plot.
The June 1985 bombing of Flight 182, which killed 329 people, came at a time of extreme bitterness in the Punjab.
In 1984 Indian troops had invaded the Golden Temple in Amritsar - Sikhism's holiest site - to flush out pro-independence Sikh militants.
Four months later Indian Prime Minister Indira Gandhi was assassinated.
Then came the bombing of Flight 182, which killed 329 people, many of them originally from the Punjab.
By 1992, Indian troops had reasserted control of the Punjab from Sikh separatists who wanted an independent state, Khalistan.
Air India flight 182 plunged into the Atlantic Ocean near Ireland
Sarbjit Singh Virk, assistant editor of Des Pardes, said he did not think the police had done enough to solve Mr Purewal's murder.
He told the BBC News website: "The police have done nothing. Maybe there were other pressures, but you hear all the time about them catching the culprit in cases after one, five, 10 years. It's been nine years now and there is no sign of the killer."
Mr Virk said: "Mr Purewal was known to the militants because he was the first overseas editor of a Punjabi paper.
"He did interview some of them and on one occasion went to Pakistan, where some of the militants were based.
"What I understand is that he was about to publish some secrets about money they had collected, supposedly for the innocent victims (of the Indian troops) in the Punjab. It had been misused, and he was planning to expose them."
A Scotland Yard spokeswoman said of the Purewal case: "There is a team of dedicated officers still working on the case and they will continue to update the file as and when necessary."
She said links with the Air India case was "speculation" and said there had been no arrests made in recent years.
Two pro-Khalistan groups - the International Sikh Youth Federation and Babbar Khalsa - remain outlawed in Britain as terrorist organisations.