Pre-trial hearings are due to begin for a Canadian teenager and a Yemeni man being held in the US detention camp at Guantanamo Bay. The youth is charged with the murder of a US doctor in Afghanistan, while the man is accused of being a bodyguard for Osama bin Laden.Legal experts have called the tribunals a sham. Professor Muneer Ahmad of the American University in Washington said: “To date no Canadian lawyer has been permitted to see Omar. “Omar’s appointed military counsel is a 31-year-old army captain who has never represented a defendant at trial in his life.” Human rights groups have also criticised rules allowing the use of secret evidence that prisoners might not be allowed to see, as well as evidence that may have been extracted during torture. US military authorities deny the process is unfair. Both suspects face life imprisonment if convicted.