Thirteen retired or serving police officers have been identified as "suspects" in the ongoing investigation into the Hillsborough disaster, the Independent Police Complaints Commission (IPCC) has said.
The commission said 11 of these had already been interviewed under caution relating to a range of offences including manslaughter as well as misconduct in a public office and perverting the course of justice.
A spokesman said the other two would be interviewed in the near future.
The spokesman said four of the 13 have been identified as suspects as part of both the IPCC's investigation and also Operation Resolve - the criminal investigation into the 1989 tragedy.
The IPCC's inquiry - the biggest it has ever undertaken - covers the actions of the police in the aftermath of the crush at Hillsborough stadium, in Sheffield, which left 96 Liverpool fans dead.
The investigation was announced after the commission reviewed the report of the Hillsborough Independent Panel, which undercovered a huge amount of new evidence about what happened during and after the tragedy.
It is examining allegations including those surrounding amendments to police statements, the actions of the police officers after the disaster and the role of West Midlands Police, which investigated what happened at the time.
Operation Resolve, under the command of assistant commissioner Jon Stoddart, the retired chief constable of Durham Police, is a new, wider-ranging criminal investigation into the disaster.
The IPCC said it could not give any further information about the people who had been arrested and how many of them had been interviewed in relation to allegations of manslaughter.