Five days after being arrested and charged with robbery, Heng Touch was sent to Prey Sar prison.

When his mother and brother visited him the next month, they learned that he had fallen ill; guards recommended that he be transferred out of his overcrowded cell, but demanded US$200 in exchange. The family could not afford to pay, and on a return visit, after learning that Heng Touch’s condition had worsened, his mother discovered bruises on his head, face and limbs and cuts on his tongue.

Heng Touch’s mother paid $30 to have him transferred to Monivong Hospital, where he later told her he had been viciously beaten by five men, sustaining lung damage and a fractured skull. Little more than six weeks after being incarcerated, Heng Touch died at Calmette Hospital.

This 2008 incident is documented in a report that was compiled by local rights groups ahead of Cambodia’s appearance today before the United Nations Committee Against Torture in Geneva, and the problems it illustrates – prison overcrowding, impunity for law enforcement, a lack of recourse for alleged torture victims – are sure to be high on the committee’s agenda.

“The situation of torture and other cruel, inhuman or degrading treatment in Cambodia is still of concern,” the rights groups said in a joint statement. “The country’s legal and judicial system is unable to effectively prevent and punish acts of torture.”

Cambodia ratified the UN Convention Against Torture in 1992, but is up for only its second review before the committee; the last was in 2002.

Although torture is punishable by up to 15 years in prison under the Kingdom’s new penal code, a difficulty in prosecuting such cases is the fact that “torture” is not clearly defined. The government said in a briefing to the CAT submitted ahead of Tuesday’s meeting that such a definition is not necessary because Cambodia “abides by the principles of international conventions”.

Am Sam Ath, a technical supervisor for local rights group Licadho, said his organisation had recorded 108 reported cases of torture in police custody in 2009 and 101 in the first 10 months of 2010. Despite these figures, the rights groups said in their report that they knew of no instances in the last five years in which law enforcement officials accused of torture had been prosecuted.

Ministry of Interior spokesman Khieu Sopheak dismissed the allegations contained in the report.

“This report was written only to satisfy donors and get their money, so it is not true. It is an accusation against our police,” Khieu Sopheak said. “To arrest a thief does not mean to welcome that thief to sleep like a guest in a prison.”

Among their recommendations for improving Cambodia’s record on torture, the rights groups suggested the establishment of a civilian body to process torture complaints and greater use of bail to ease overcrowding in the prison system, which was operating at 173 percent of capacity as of June. The groups also called for the closure of controversial “Social Affairs Centres”, where sex workers, children and the homeless are often detained without due process, and where reports of abuse are widespread.

The meeting in Geneva comes just two weeks after government officials threatened to close the UN human rights office in Phnom Penh. Foreign Minister Hor Namhong backed away from these statements last week, saying there was “no decision to close this office yet”.