The Australian Security Intelligence Organisation (ASIO) may have made publicly available secret files opened on ''persons of interest'' during its Cold War on home-grown communism, but surveillance footage from that time is apparently not so easily accessed. Filmmaker Haydn Keenan, who made 1980s Australian cult movies Going Down and Pandemonium, scoured the ''darkened corners'' of the National Archives to find the astounding, disturbing and blackly amusing footage revealed in his four-part 2013 Walkley-nominated series, Persons of Interest.

''It was extremely difficult to get access to the archival footage, as the existence of it was not acknowledged for quite some time,'' Keenan says. ''There seemed to be huge gaps in what was available. I thought, well, either they stopped shooting surveillance film, or it is around somewhere. We ended up tracking down about 100 hours, so that was a massive breakthrough.''

Footage of the targets profiled in the series - Roger Milliss, Michael Hyde, Frank Hardy and Gary Foley - is chilling when cut with interviews with the targets themselves, along with academics and former ASIO spies. Narrated by Keenan, with the eerily soothing voice of actress Mercia Deane-Johns reading the files, the series reveals a human aspect to this notorious chapter of Australian history, from both sides of the operation.

The targets, when filmed reading their deeply personal and damning files for the first time, and the men who spied on them, when recalling their work and its damage to their own lives, are visibly overcome with bitterness and regret. One prominent Australian, whom Keenan will not name, pulled out of the series when his ASIO file revealed his lifelong best friend was a spy.