Kamiti Prison. One British settler described an interrogation by the colonial police force: On 22 November 1954, Colonel Arthur Young sent a letter to Governor Evelyn Baring about the "inhumanity" of various parts of the security forces amid his investigations of wrongdoing: In January 1955, Baring sent a telegram to Alan Lennox-Boyd, the Secretary of State for the Colonies and a cabinet minister, and told them that eight white European officers who had been accused of serious crimes, including accessory to murder, would be given immunity from prosecution. One district officer was accused of the "beating up and roasting alive of one African". A Kenyan Regiment Sergeant and a field intelligence assistance had been implicated in the burning of two further suspects "during screening operations". "I had not myself realised until today that the extension of the principle of clemency to all members of the security forces involved so many cases with Europeans as principals," wrote Baring. In 1956, Baring's administration devised the "dilution technique" – a system of assaults and psychological shocks to detainees, to force the compliance of the toughest Mau Mau supporters. Lennox-Boyd was told that one commander, Terrence Gavaghan, had developed the techniques at the Mwea camps in central Kenya – and he needed permission to treat the worst detainees in a "rough way". Baring telegrammed the Colonial Secretary in London asking for his approval to use "overpowering" force, and the cabinet minister's approval came within weeks. A ministerial delegation saw firsthand prisoners beaten for refusing to don camp clothes. Ringleaders of the "Mau Mau moan" – a chant of defiance – were singled out for special punishment. They were beaten and forced to the ground. Once there, a boot was placed on their throat while mud was forced into their mouths. Gavaghan also explained how difficult detainees would be subjected to the "third degree". "The measures adopted were to be kept awake all night, having water thrown at him and to be beaten up on a variety of pretexts." One Hanslope Park document is a letter between Kenyan Special Branch police officers about treatment of "fanatical" detainees at the Mwea camps. In June 1957, Eric Griffith-Jones, the attorney general of the British administration in Kenya, wrote to Baring, detailing the way the regime of abuse at the colony's detention camps was being subtly altered. He said that the mistreatment of the detainees is "distressingly reminiscent