Director of Public Prosecutions Keir Starmer QC has told ITV News he will meet with the families of Hillsborough victims on Friday after they voiced concerns over the slow progress of the inquiry into the 1989 disaster.
He added that he was "well aware" of the families concerns.
The police watchdog is appealing for witnesses as part of its investigation into how West Midlands Police conducted its inquiries into the Hillsborough disaster.
Deborah Glass, deputy chair of the Independent Police Complaints Commission, said: "We have already had a number of people contact us with concerns that their statements were amended and we have no doubt there are others who have not contacted us.
"We want to be able to present as full as possible a picture of witness evidence both for the inquests and the criminal investigations."
To date 90 pocket notebooks have been handed into the police watchdog by retired and serving police officers from South Yorkshire Police that contained notes on the day of the Hillsborough disaster, the IPCC has said.
In a statement the police watchdog added: "The books will be recovered by IPCC investigators this week to be analysed to determine whether they contain specific entries relating to Hillsborough."
The police watchdog has revealed that statements of 74 more officers at the Hillsborough stadium disaster "may have been amended."
The Independent Police Complaints Commission made the revelation as it provided an update on the setting up of its inquiry into the tragedy:
– Deborah Glass, Independent Police Complaints Commission Deputy Chair
From our work on this we have recovered West Midlands policy books that have never been seen by previous inquiries.
We have identified that the statements of 74 more officers may have been amended.
We have also uncovered material which would suggest that fans’ witness accounts may have been altered.
We have recovered pocket notebooks from officers who were on duty on the day of the match.
We are in the process of interviewing all the surviving officers whose accounts were amended.