More than 500 people have responded to a fresh appeal for witnesses to the 1989 Hillsborough disaster.
The Independent Police Complaints Commission launched an appeal earlier this week as part of an investigation into police handling of the tragedy, in which 96 Liverpool football fans died.
The probe has already unearthed evidence that police altered statements submitted by officers on the day of the disaster.
On top of that, the IPCC has found evidence suggesting that in a subsequent inquiry, statements from supporters present on the day were also doctored, AFP reports.
About 12,000 people were interviewed for that inquiry and the complaints commission says it wants to hear from those people, as well as anyone who has not spoken to any previous investigating teams.
The Liverpool fans were crushed to death amid overcrowding at one end of Hillsborough Stadium in Sheffield, northern England, before an FA Cup semi-final between Liverpool and Nottingham Forest in April 1989.