A single bullet could hold the key to last year’s murder of 17 Sri Lankan aid workers, which the government and Tamil Tiger rebels still blame on each other.

Michael Birnbaum, a British barrister observing the inquest for the International Committee of Jurists, says that a 5.56 mm bullet is missing from evidence gathered at the scene of the crime.

The Tigers mainly use AK-47 assault rifles, which fire 7.62 mm rounds, while Sri Lanka’s elite military and police units use American M-16 rifles, which fire 5.56 mm bullets.

The 17 local staff for Action Against Hunger were all shot execution-style in the town of Muttur, 140 miles northeast of Colombo, amid heavy fighting between the Tigers and government forces in August last year.

Dr Malcolm Dodd, an Australian pathologist who attended a post-mortem last October, reported that eight bullets were recovered from seven bodies -- seven 7.62 mm and one 5.56 mm.

However, a government analyst later concluded that all the bullets were 7.62 calibre, according to ICJ.

“There is, therefore, evidence to indicate that the 5.56 calibre bullet was removed from the evidence... and that another bullet of a different type was substituted,” ICJ said in a statement.

“Given this new information, the ICJ is calling for the president of Sri Lanka to order renewed, impartial and thorough investigations into the killing of the 17 aid workers... and to ensure those responsible are prosecuted.” The government has denied any involvement and says a presidential commission is investigating the killings.

But international observers say that probe is going nowhere and Nordic ceasefire monitors blame government forces.

ICJ has also frequently criticised the government’s investigation, complaining that security forces in the town at the time were not even interviewed, among other irregularities.

The group’s latest statement threatens to embarrass the government just as Sri Lanka’s top foreign aid donors are meeting in Oslo to discuss ways of halting the bloodshed in the island nation.

More than 5,000 people have been killed on both sides since a 2002 truce, brokered by Norway, began to unravel 19 months ago.

The Tigers have been fighting since 1983 for an independent homeland in the northeast to protect Sri Lanka’s Tamil minority from discrimination by the Sinhalese majority.

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