A leading Sri Lankan human rights group has called for an open investigation into an alleged mass grave at Chemmani in the northern Jaffna peninsular.

Activists are desperate to keep the mass grave issue in the public eye fearing that the government might try to delay any investigation.

The university-based human rights organisation says there have been inexcusable delays since the allegations were first made in July 1998 by a soldier during his trial for murder.

The former corporal, Rajapakse, was found guilty of murdering a student, her mother, brother and a neighbour in 1996 - a time when the army is accused of carrying out several abductions and killings in Jaffna.

He told the court that up to 300 bodies had been buried at Chemmani.

Eight months later, a team, including a forensic scientist, went to the site, but it was not certain they were in the right place.

Rajapakse himself is due to accompany them in another trip on 15 June this year.

Foreign experts

The human rights group has also called for foreign forensic experts to be invited to any exhumation, and has expressed concern about the Attorney General's department handling the case.

According to the group, it seems unlikely that the investigation would be concluded soon, as had been promised.

The office of the UN High Commissioner for Human Rights said they were contacted last year by Sri Lanka's own human rights commission for information about exhumations but had heard nothing more.

The exhumation of the alleged grave is a crucial issue in Jaffna. One Tamil leader said they believed the arm of the law was never extended to them when they suffered state violence and that steps now had to be taken to hold the guilty accountable.