Detectives and the authority were concerned that these events might have closed potential avenues of inquiry when they submitted the findings of the six-month investigation to the Crown Prosecution Service yesterday.
The report may prove crucial to the outcome of the forthcoming appeal by Malcolm Kennedy against his conviction and life sentence for the murder of Patrick Quinn, his cell-mate at Hammersmith police station, west London. For in what was a unique investigation by the complaints authority, this was the first time a convicted person's defence formed the entire basis of a complaint against police.
No details of the conclusions or recommendations of the report were revealed and it will be up to the prosecution service to decide whether any officers will face criminal charges.
Yesterday, Tim Cook, Kennedy's solictor, said: 'I find it disturbing that the initial Crown Prosecution file is missing.'
Kennedy, 44, in Wormwood Scrubs, and Mr Quinn, 56, were arrested for drunkenness in separate incidents 'for their own protection' on 23 December 1990.
By the early hours of the following morning, Mr Quinn had been kicked to death.
The prosecution said that Kennedy, in his drunken stupor, had subjected him to a manic and unprovoked attack.
Kennedy claimed police incriminated him.
The Police Complaints Authority took up his claims and the investigation headed by Superintendent Tom Wright, of Thames Valley Police, and supervised by Kiramjit Singh, was launched.
In a clear criticism of the CPS and police, Mr Singh, said: 'The statement issued by the authority today demonstrates how thoroughly this particular investigation has been undertaken despite the constraints of not being able to pursue certain lines of inquiry over which we have no control.'