Doctors and psychologists the CIA employed to monitor its enhanced interrogation" of terror suspects came close to, and may even have committed, unlawful human experimentation, a medical ethics watchdog has alleged. Physicians for Human Rights (PHR), a not-for-profit group that has investigated the role of medical personnel in alleged incidents of torture at Guantnamo, Abu Ghraib, Bagram and other US detention sites, accuses doctors of being far more involved than hitherto understood. PHR says health professionals participated at every stage in the development, implementation and legal justification of what it calls the CIA's secret "torture programme". The most incendiary accusation of PHR's latest report, Aiding Torture, is that doctors actively monitored the CIA's interrogation techniques with a view to determining their effectiveness, using detainees as human subjects without their consent. The report concludes that such data gathering was "a practice that approaches unlawful experimentation". Human experimentation without consent has been prohibited in any setting since 1947 [with] the Nuremberg Code, which resulted from the prosecution of Nazi doctors. In April, a leaked report from the International Committee of the Red Cross found that medical staff employed by the CIA had been present during waterboarding, and had even used what appeared to be a pulse oxymeter, placed on the prisoner's finger to monitor his oxygen saturation during the procedure. PHR is calling for an official investigation into the role of doctors in the CIA's now widely discredited programme. It wants to know exactly how many doctors participated, what they did, what records they kept and the science that they applied.