On the 28 February 1986, Olof Palme, Sweden's social democratic Prime Minister, was shot dead as he was walking home from the cinema which he had attended with his wife. 20 years on and still there are no answers, only theories. Although there seem to have been several witnesses who saw men with walkie-talkies in the vicinity on the night in question, the Swedish police force seems to have closed ranks. According to the chief investigator on the case,...