a turning point for the production came when the recently retired john thorburn agreed to act as consultant. detective chief superintendent thorburn, a former head of the manchester murder squad, had been stalker's number two on the investigation, in charge of the day-to-day running of the inquiry, while stalker flew in from time to time to supervise as required. thorburn had never spoken to the press about his role, despite the best efforts of both kosminsky for yorkshire's "first tuesday", and peter taylor of the bbc's series "panorama", to persuade him. however, in january 1988 the attorney general, sir patrick mayhew, announced to parliament that despite evidence that ruc officers had obstructed and perverted the course of justice, he had advised the director of public prosecutions for northern ireland that it would not be in the public interest for those officers to be prosecuted, for reasons of national security. this changed thorburn's mind. according to kosminsky, "he didn't do it for the money... i just happened to hit him at a time when his frustration hit a peak."