An investigation into the Hillsborough disaster and its aftermath has identified an additional 55 police officers whose statements on the tragedy may have been amended.
The statements are in addition to 164 altered accounts already identified by the Hillsborough Independent Panel in September last year, said the Independent Police Complaints Commission (IPCC).
The panel originally found that 116 of the 164 statements had been amended to remove or alter comments "unfavourable" to South Yorkshire Police.
Ninety six Liverpool fans were killed in a crush at Sheffield's Hillsborough stadium on April 15 1989 during the team's FA Cup semi-final against Nottingham Forest.
The IPCC announced on October 12 that it would be launching an independent investigation into allegations surrounding the aftermath of the Hillsborough disaster, following a review of the Hillsborough Independent Panel's report.
This investigation is reviewing allegations surrounding amendments to statements, the actions of the police officers after the disaster and the role of West Midlands Police and those who investigated what happened at the time. A separate team led by by former Durham chief constable Jon Stoddart is investigating a range of organisations involved in the preparation for the event and what happened on the day.
The IPCC is managing the strand of this investigation which is examining the actions of the police. In its monthly update, the IPCC said its Hillsborough Contact Team had received more than 230 pieces of correspondence since October, more than 50 relating to statements.
Deborah Glass, IPCC deputy chairwoman, said: "The IPCC knows the people who have contacted us are the tip of the iceberg. Therefore preparations are ongoing for an appeal for witnesses to the disaster and this is expected to be conducted in the autumn. The preparations will include work with appropriate agencies to provide welfare support where needed to those who will have to recount the traumatic events of 15 April 1989."
The IPCC has recovered 97% of the documentation originally supplied to the panel and identified additional documentation not previously disclosed. The police watchdog expects to have a team of 70 to 100 staff on the investigation.
Fresh inquests into the deaths of the 96 victims are set to begin by March 31 next year. Last December, verdicts of accidental death from the original inquest in March 1991 were quashed. The action was taken after the Hillsborough Independent Panel studied thousands of documents and reported there had been a huge cover-up of what happened at Hillsborough and its aftermath.