Unravelling Anni Dewani murder evidence
19 September 2013 Last updated at 06:09 BST
South African police "failed" to test evidence against key facts in Anni Dewani's murder, according to a leading forensic scientist.
Mrs Dewani was shot dead on her honeymoon in South Africa in 2010. Her husband, Shrien, is accused of ordering her murder.
Now the BBC has obtained police files on the case including CCTV footage, phone records and forensic evidence.
The South African police say it would be improper to engage with the media on the merits of the case as trial by media would violate Shrien Dewani's right to a fair trial.
Members of Anni's family also have criticised the BBC for conducting what they say is trial by television and have called on Shrien Dewani to return to South Africa to answer the charges.
Shrien Dewani denies any involvement in Anni's murder and remains sectioned under the Mental Health Act.
You can watch BBC Panorama - The Honeymoon Murder: Who Killed Anni? on Thursday 19th September at 9pm.