Hillsborough: BBC Panorama speaks to relatives and witnesses
20 May 2013 Last updated at 01:44 BST
An investigation by the BBC's Panorama into the cover-up that followed the Hillsborough disaster has revealed crucial evidence from an off-duty police officer, which was undermined at the original inquest into the tragedy, was true.
The officer's account would have challenged a controversial decision by the coroner to set a time limit beyond which dying fans could not have survived.
Panorama spoke to relatives of people who died, and witnesses to the disaster.