Twenty-two people have been identified as "suspects" by two investigations into the Hillsborough disaster.
On Thursday, the Independent Police Complaints Commission (IPCC) confirmed 13 officers, retired or serving, had been identified in its inquiry.
Operation Resolve, the criminal investigation into the tragedy, has also identified 13 people, four of whom feature in the IPCC inquiry.
Fresh inquests into the 96 deaths will begin in Warrington on Monday.
The IPCC is examining police conduct following the tragedy.
The football supporters were crushed during the FA Cup semi-final between Liverpool and Nottingham Forest at Sheffield Wednesday's stadium on 15 April 1989.