Remember when the CIA insisted it had only waterboarded three high-level al-Qaida terror suspects? Turns out that wasn't quite true. A new report from Human Rights Watch claims that more than a dozen Libyan dissidents were tortured by the CIA – then returned to Tripoli for more.

The report is based on Libyan intelligence service documents found after dictator Muammar Gaddafi was deposed, and on interviews with 14 former Gaddafi opponents, some of whom now hold positions in the new Libyan government.

It says that Britain's MI6 and other western intelligence agencies helped as well, and that the torture went beyond waterboarding. According to the New York Times, interviewees reported being "stripped naked and chained to walls; being left in diapers in dark cells for weeks or months at a time without being allowed to bathe; being forced into painful stress positions", and more.

The news is yet more confirmation of what many have long suspected: that western intelligence agencies rewarded Gaddafi for renouncing terrorism and swearing off nuclear weapons by co-operating in the rendition and torture of Libyan dissidents.

As if that wasn't bad enough, US attorney general Eric Holder announced last week that no one – not one person – would be prosecuted for any CIA abuses of detainees, even in the two cases where suspects died.

Learn more: Read the full Human Rights Watch report – it's every bit as appalling as you'd expect.

Sources: New York Times, Guardian, Human Rights Watch