The police watchdog will announce tomorrow what action it plans to take over allegations made in a damning report on the Hillsborough disaster.
Claims were made last month that officers had staged a shocking cover-up after the tragedy in an attempt to shift blame on to the 96 victims.
The Hillsborough Independent Panel found that 164 police statements were altered, 116 of them to remove or change negative comments about the policing of the match and the ensuing disaster.
Watchdog the Independent Police Complaints Commission (IPCC) said it would review the panel's findings as well as those of previous inquiries into the tragedy.
If the IPCC's predecessor, the Police Complaints Authority (PCA), has already investigated certain matters it could stop the IPCC from looking at them again.
After the report was published, a complaint was made to the IPCC that Sir Norman Bettison, who was a chief inspector in South Yorkshire at the time, had supplied misleading information in the wake of the disaster.
A second element of the complaint was over comments made by Sir Norman, currently Chief Constable of West Yorkshire Police, after the report was published.
He said that Liverpool fans' behaviour made policing the tragedy in 1989 "harder than it needed to be", sparking fury and calls for him to resign.
Last week Sir Norman announced that he is to retire in March, saying: "Recent weeks have caused me to reflect on what is best for the future of policing in West Yorkshire and I have now decided to set a firm date for my retirement."
He said he hoped his departure would allow the IPCC to "fully investigate allegations that have been raised about my integrity".
Sir Norman had previously denied altering any statements or asking for any to be altered. An officer cannot be subject to misconduct proceedings after they have retired.
Relatives of the 96 victims welcomed Sir Norman's decision to retire, but his service in policing was defended by senior officer Sir Hugh Orde.
Margaret Aspinall, who lost her 18-year-old son James in the tragedy and is chairwoman of the Hillsborough Families Support Group, said: "I'm absolutely delighted that he's going."
Sir Hugh, president of the Association of Chief Police Officers, said: "Sir Norman Bettison has served the public as a police officer with distinction for nearly 40 years, and at the rank of chief constable since 1998.
"His depth of knowledge and experience is highly regarded within the service and he will be a great loss to policing."