By Guy DeLauney
BBC News, Phnom Penh
The tribunal has heard details of mass murder and torture
The international prosecutor at the Khmer Rouge tribunal has warned that the process is failing to make a connection with the Cambodian people.
Robert Petit said he was also concerned about political interference at the special courts.
The Canadian official has just announced his resignation after three years of leading the prosecution of former Khmer Rouge leaders.
He said his resignation was not connected to problems at the tribunal.
But at a news conference to announce his impending departure he outlined his concerns about several key areas at the special courts.
It's a very bad sign for Cambodia if any elected official thinks they have the right to influence any court process
Robert Petit, Khmer Rouge Tribunal
Mr Petit said the tribunal had failed to explain itself to its most important audience - the Cambodian people.
The first trial of a former Khmer Rouge leader started three months ago.
But Mr Petit said that a lack of funding for outreach work had limited its impact on the public.
The prosecutor said he was also worried about the role of the Cambodian government.
WHO WERE THE KHMER ROUGE?
Maoist regime that ruled Cambodia from 1975-1979
Founded and led by Pol Pot, who died in 1998
Abolished religion, schools and currency in a bid to create agrarian utopia
Up to two million people thought to have died from starvation, overwork or execution
Prime minister Hun Sen has been critical of proposals to investigate more former Khmer Rouge leaders.
But Mr Petit says that shouldn't be a decision for politicians.
"It's a very bad sign for Cambodia if any elected official thinks they have the right to influence any court process," he said.
"By continuing - us, the court - to do our job, according to the evidence of the law, hopefully we can provide a counter-weight to that," he said.
Mr Petit is the third member of the international prosecution team to resign this year.
But he says his departure should have no impact on the progress of the trials as his colleagues have already taken over much of his work.