"Hussein Onyango Obama, Mr Obama’s paternal grandfather, became involved in the Kenyan independence movement while working as a cook for a British army officer after the war. He was arrested in 1949 and jailed for two years in a high-security prison where, according to his family, he was subjected to horrific violence to extract information about the growing insurgency."
 http://www.timesonline.co.uk/tol/news/world/africa/article5276010.ece