A three-year undercover investigation into the world's most powerful gun lobby ended last year with an explosive report by Al Jazeera's investigative unit that revealed a link between the National Rifle Association and Australia's far right. Journalists from the unit walk us through how they got the story — which is the focus of a newly published book.For more:How to sell a massacre: NRA's playbook revealed In this episode:Peter Charley, executive producer for Al Jazeera's Investigative Unit; Al Jazeera senior producer Jeremy Young.Connect with The Take: Twitter (@ajthetake), Instagram (@ajthetake) and Facebook (@TheTakePod).