Link to The Guardian, October 2010:

The UN's own Office of the High Commissioner for Human Rights (OHCHR) has described the conditions at Prey Speu as "appalling" with people "illegally confined and subject to a variety of abuses of power by the staff that included sub-humane conditions of detention, extortion, beating, rape, sometimes resulting in death and suicide".

But the department that runs Prey Speu still gets money directly from the UN's children's fund, Unicef and the centre is also supported by several international NGOs.

Prey Speu has a daily food budget of 3,000 riels (47p) for each detainee. Generally, they are fed a watery rice gruel in a plastic bag twice a day.

Guards at three-metre gates said the facility was a voluntary welfare centre and detainees were free to leave whenever they wanted. Asked why the gates were padlocked, guards said it was to keep people out.

From the Phnom Pehn Post several months ago:

According to the report, a total of 539 homeless people were rounded up in 2014, and 445 of them were sent to Prey Speu; a centre where, since its opening in 2004, staff have been accused of abuse, rape and even murder.

Following the allegations, Prey Speu shut down in June 2012, but was reopened the next year, rebranded as the Por Sen Chey Vocational Training Centre.

The facility seems to have changed in name only, with regular reports of subhuman conditions emerging from the centre.

While most people sent there quickly escape over the centre’s low external wall, others remain in permanent residence.

The report says there are currently 72 homeless people staying at Prey Speu, including children, elderly, mentally ill and disabled people.

3 days ago in The Cambodia Daily:

The U.N. and two other NGOs toured the notorious Prey Speu social affairs center in Phnom Penh yesterday, said an official, but he refused to reveal the outcome of the visit.

Officially called the Pur Senchey Vocational Training Center, it has again been in the headlines after CNRP and CPP lawmakers from the National Assembly’s health commission on Tuesday toured the facility. According to detainees and rights groups, physical and sexual abuse are rife at the center.

Sorn Sophal, director of Phnom Penh’s social affairs department, said U.N. agencies, including Unicef, were joined by Friends International and another unnamed NGO in visiting the center yesterday, but he would not give details. “If you want to know details, you can call the U.N.,” he said.

Neither the U.N.’s Office of the High Commissioner for Human Rights nor Unicef immediately responded to requests for comment.

Mr. Sophal said Prey Speu’s remaining detainees were at the center of their own volition. “The remaining people do not want to leave the center because they do not have relatives or a permanent home,” he said.

It appears that able-bodied people are able to leave by climbing a wall, and most leave immediately after arrival. This is one of the weirdest stories I've read in a while.