The police watchdog has written to a chief constable expressing concern over comments in an email about the Hillsborough disaster that were "at best ill-judged and at worst offensive and upsetting".
South Yorkshire chief David Crompton sent an email to his senior staff last year which appeared to suggest a campaign group representing families of those who died was not telling the full truth about the 1989 tragedy.
The email read: "One thing is certain - the Hillsborough Campaign for Justice will be doing their version ... in fact their version of certain events has become 'the truth' even though it isn't!! I just have the feeling that the media 'machine' favours the families and not us, so we need to be a bit more innovative in our response to have a fighting chance otherwise we will just be roadkill."
The internal email, which came to light following a Freedom of Information request, was sent as part of South Yorkshire Police's preparations for the publication of the Hillsborough Independent Panel report last year. It discussed how the force could use its website to respond to the findings of the panel.
When the report was published, it provoked widespread condemnation of the force's response to the disaster at Sheffield Wednesday's ground in April 1989, which left 96 Liverpool fans dead. It revealed how dozens of police statements had been altered to portray police in a better light.
South Yorkshire Police's response to the tragedy is currently subject to a huge inquiry by the Independent Police Complaints Commission (IPCC). Last month, the Police and Crime Commissioner of South Yorkshire, Shaun Wright, wrote to the IPCC when he was made aware of the emails and associated documents.
On Tuesday, IPCC Commissioner Nicholas Long said the majority of the emails and documents he considered "raises no issues". But he said one email from the chief constable "caused me concern".
He said: "It referred to preparing what 'amounts to the case for the defence' and stated that the 'Hillsborough Campaign for Justice's ... version of certain events had become the truth even though it isn't'. I consider that this is at best ill-judged, and at worst offensive and upsetting. I have written to Chief Constable Crompton to express these views.
"Families and individuals affected by the Hillsborough tragedy, along with the wider public, will rightly be concerned over the apparent attitude displayed by this communication within the highest ranks of the force which is currently under investigation in relation to the actions of its officers and staff around the disaster."
Last week, Mr Crompton said the email, sent to his assistant chief constable and head of press and communications, was not meant to cause offence. He said: "It was never intended to cause any offence and I apologise if it has done so. Nor was it intended to challenge the integrity and views of those who lost loved ones in the Hillsborough disaster. Following the publication of the panel's report, I said in the most forthright terms that I supported the findings and that is still my position."