Cambodian visitors view an exhibit of pictures showing former Khmer Rouge leader Kaing Khek Iev, at a former regime's prison in Phnom Penh.

A day after the pre-trial chamber announced it would accept auxiliary briefs in the case of Tuol Sleng prison chief Duch, civic groups say they will submit documents to the tribunal courts on whether he should stay in jail ahead of his trial.

Groups or individuals now have less than 30 days to submit their "friends of the court" briefs to the pre-trial chamber of the tribunal in Duch's case.

Duch has been held without trial since 1999, and the pre-trial chamber's first task will be to rule on the legality of his detention in tribunal's case against him. He was charged with crimes against humanity in July and turned over to the tribunal from the custody of the military courts.

Several former Tuol Sleng prisoners and an opposition party member said Wednesday they would not file, while other community leaders praised the announcement that the public would have some degree of participation in the trials of former Khmer Rouge leaders.

"We must rely on the legal experts, and we are waiting to see what the public has to say about Duch," said Seng Theary, head of the Center for Social Development.

Sok Samoeun, Cambodian Defender's Project director, said his organization was considering whether they would submit a brief or not.