Lawers for former Olympic rower Rob Hamill have called for access to the case file in the Khmer Rouge tribunal’s third case as they prepare to appeal the controversial rejection of his civil party application.

In a request dated May 12 and made public on the court’s website yesterday, the New Zealander’s lawyers argued that their continued lack of access to the case file would prevent them from effectively defending Hamill’s right to participate.

“This request is made in the interests of justice and on grounds of procedural fairness,” the lawyers wrote, noting that in Case 002, in which Hamill has already been accepted as a civil party, lawyers received access to the case file ahead of decisions on their clients’ admissibility.

“Civil Party applicants cannot form meaningful legal and/or factual grounds of appeal without knowledge of basic matters pertaining to the case file,” they said.

Hamill’s brother Kerry was captured by the Khmer Rouge in 1978 while sailing with friends in the Gulf of Thailand before being taken to S-21 prison in Phnom Penh and executed. Rob Hamill was present to testify about the ordeal in 2009 during the tribunal’s first trial, that of former S-21 prison chief Kaing Guek Eav, better known as Duch.

The suspects in Case 003 remain officially confidential, though court documents reveal them as former KR navy commander Meas Muth and air force commander Sou Met.

Hamill says Meas Muth in particular played a “pivotal role” in his brother’s capture, and in a statement earlier this month, tribunal co-prosecutor Andrew Cayley confirmed that the “capture of foreign nationals off the coast of Cambodia and their unlawful imprisonment” figures in the Case 003 investigation. In view of this information, Hamill called the rejection of his application earlier this month by the court’s co-investigating judges “outrageous and unfounded”.

Anne Heindel, a legal adviser at the Documentation Centre of Cambodia, said she believed all 318 people who have applied to be civil parties in Case 003 will ultimately be rejected, as the judges have no intention of sending the case to trial.

“The co-investigating judges are clearly doing everything in their power to limit public information and public knowledge of what’s going on,” she said.