South African police failed to test key evidence in the Anni Dewani murder case, according to a leading forensic scientist. Anni Dewani was shot dead on her honeymoon in Cape Town three years ago and her husband Shrien is awaiting extradition to South Africa after being accused of hiring hitmen to murder her. The BBC's Panorama programme has obtained secret police files on the case. Jeremy Vine reports. You can watch BBC Panorama - The Honeymoon Murder: Who Killed Anni? on Thursday 19th September at 9pm, or online here.