Former Strathclyde PC Donald Morrison, who believes the firebrand lawyer was murdered by British intelligence in 1985, gave a 12-page witness statement to detectives three years ago.
But despite what he regards as “vital new” information being given to the former Northern Constabulary, no further action was taken by the Crown Office.
The 72-year-old, of Morayshire, repeatedly asked for a copy of his witness statement under Freedom of Information legislation and finally received a document earlier this month. However, he says it is a “substantially shorter, altered version” of the testimony he gave in 2011.