The South African Human Rights Commission is to investigate the confinement of six Pretoria prisoners held in solitary isolation for 23 hours a day for nearly a month. The six were placed in isolation cells in a basement in Kgosi Mampuru II Prison - dubbed ''the Cave'' - after being labelled troublemakers. They were representing prisoners from Odi Prison, north of Pretoria, who threatened to go on a hunger strike over a lack of parole programmes.The commissioner of correctional services in Pretoria, Zebilion Monama, ordered the isolation of the inmates on June 25.They have been in the Cave ever since, according to their lawyer, Connie Ntsoko.She has being trying to bring their plight to the attention of correctional services since July 2.The Correctional Services Department yesterday failed to respond to e-mail and SMS requests for comment.According to a prisoner who has been held in the Cave, it is at least 10m underground and its cells measure 3m by 2m, with no windows.Prisoners there are let out of their cells for only an hour a day, in an inner courtyard, and may not interact with anyone else.The lights in the Cave are controlled from outside."It was terrible. You hear people screaming, crying, begging to be let out, promising their souls, anything to get out of there ." a former inmate who was held underground for six months said."The cells are tiny . You have no idea when it is day or night."You come out when the prison manager decides you come out."The policies of the Department of Correctional Services state that prisoners may be held in isolation for only seven days. This, according to Wits Justice Project researchers, can be extended by a week, but only if strict guidelines have been met.Ntsoko and the Judicial Inspectorate for Correctional Services have demanded an explanation for the "unlawful" detention and segregation, but none has been provided.The isolation of the inmates appears to flout the internationally recognised Mandela Rules, adopted by South Africa, which prohibit solitary confinement of more than 15 days and prohibits cruel, inhuman or degrading treatment or punishment of prisoners.Commissioner Danny Titus confirmed the Human Rights Commission would investigate the detentions. It would meet department officials this week."We hope to obtain figures of how many prisoners are placed in solitary confinement and the conditions they are placed in," he said.In its 2013-2014 annual report, the Judicial Inspectorate for Correctional Services revealed that 8 397 inmates were held in isolation, with 23 cases of inhumane treatment of inmates cited.Inspectorate spokesman Umesh Raga said an official would be sent to the prison today.The inspectorate had made inquiries to the department about the inmates and advised that their continued segregation would be unlawful. But, said Raga, it had received no response.Lukas Muntingh, co-founder of the Civil Society Prison Reform Initiative, said extended periods of solitary confinement caused severe psychological harm."It is deemed a cruel and unnatural form of punishment. While justifiable in specific circumstances and for a short duration, it is not justifiable when it runs into weeks," he said.Ruth Hopkins of the Wits Justice Project said that in the past solitary confinement was used as punishment, but nowadays it was meant to be used to deal with prisoners who were escape risks or threats to others or themselves.The area commissioner and judicial inspectorate had to be informed of all isolations, and prisoners had to be visited daily by a medical practitioner, Hopkins said.The project's research showed that inmates were regularly isolated for longer than the seven days allowed.Hopkins said there were documented cases of whistle-blowers placed in solitary confinement to silence them."In Port Elizabeth, a St Albans Prison inmate who witnessed the torture of 231 prisoners in 2005 was placed in isolation to silence him."Robert Peacock, a criminology professor at the University of the Free State, said long periods in solitary confinement could lead to "re-enactment of traumatic experiences and could drive an individual to kill themself"...