It is being called "the voice from the grave", a remarkable and accusing article written by one of Sri Lanka's best-known journalists and published days after he was murdered in a hail of gunfire.

In a 2,500 word editorial, Lasantha Wickrematunge foresees his own death, hints at the identity of the killers from within the ranks of Sri Lanka's government, and lays out a gripping and detailed account of what he sees as his country's descent into persecution of citizens and flouting of democracy.

"When finally I am killed, it will be the government that kills me," he wrote. Addressing Sri Lanka's president, Mahinda Rajapakse - a close friend - he says: "In the wake of my death I know you will make all the usual sanctimonious noises and call upon the police to hold a swift and thorough inquiry. But like all the inquiries you have ordered in the past, nothing will come of this one, too. For truth be told, we both know who will be behind my death."

Wickrematunge was shot in the head in Sri Lanka's capital, Colombo, by two gunman on a motorcycle as he drove to work on Thursday. More than 4,000 people attended his funeral yesterday, including opposition leaders and human rights activists.

In its 15 years of existence his paper, the Sunday Leader, became well known as the island's best independent newspaper. It took an impartial line on the vicious civil war ravaging the island between the Sinhala-dominated government and the Tamil Tigers fighting for autonomy.

It produced a series of scoops about dissension within the government and, in spite of heavy censorship of all on-the-ground reporting of the war, it regularly exposed atrocities for which the security sources were suspected.

Wickrematunge had suffered three attacks before last week. He was twice assaulted by unknown assailants and his house was sprayed with machine-gun fire. "Countless [Sri Lankan] journalists have been harassed, threatened and killed. It has been my honour to belong to all those categories and now especially the last," said his article, published under the headline "And then they came for me".

The government has made a series of military gains over the Tigers in the last two weeks, capturing their political capital and reopening the main road from Colombo to Jaffna by seizing the important Elephant Pass. In the editorial Wickrematunge said this would not bring victory - a sign he wrote his article very recently. "A military occupation of the country's north and east will require the Tamil people of those regions to live eternally as second-class citizens, deprived of all self respect. Do not imagine that you can placate them by showering "development" and "reconstruction" on them in the post-war era.

"The wounds of war will scar them forever, and you will also have an even more bitter and hateful diaspora to contend with," he wrote.

A member of the Sinhala elite, Wickrematunge said: "Unknown to most of the public, Mahinda and I have been friends for more than a quarter century. Indeed, I suspect that I am one of the few people remaining who routinely addresses him by his first name." He pointed out that he still had frequent late-night meetings with the president where they chatted and even joked.

"You have told me yourself that you were not greedy for the presidency. You did not have to hanker after it: it fell into your lap. You have told me that your sons are your greatest joy, and that you love spending time with them, leaving your brothers to operate the machinery of state. Now, it is clear to all who will see that that machinery has operated so well that my sons and daughter do not themselves have a father."

The editor ends his article appealing to his readers: "If you remember nothing else, remember this: the [Sunday] Leader is there for you, be you Sinhalese, Tamil, Muslim, low-caste, homosexual, dissident or disabled. Its staff will fight on, unbowed and unafraid, with the courage to which you have become accustomed. Do not take that commitment for granted. Let there be no doubt that whatever sacrifices we journalists make, they are not made for our own glory or enrichment: they are made for you. Whether you deserve their sacrifice is another matter. As for me, God knows I tried."

A spokesman for Sri Lanka's high commission in London said last night: "There was condemnation last week by the president of the murder." Asked if the president or government had responded to the dead editor's article in the Sunday Leader, he said: "There has been no reaction."

The civil war

The Liberation Tigers of Tamil Eelam - designated a terrorist organisation by the US, the EU and India - are fighting for an independent state in the north and east of Sri Lanka. The 25-year civil war has killed 70,000 people but was only officially acknowledged in January last year when the government ended a 2002 ceasefire, saying "terrorists" had used the truce to re-arm and plan attacks.

Tamils, who are predominately Hindu and make up 12% of Sri Lanka's population, claim they are discriminated against by the Buddhist Sinhalese majority.

The Sri Lankan military has achieved a string of major victories against the rebels in recent months, including the capture of the Tamil Tiger administrative capital of Kilinochchi a week ago.