How China spies on dissidents in Australia

A former Chinese spy has revealed the lengths taken by its security services to track down dissidents overseas, including in Australia, and get them back home. Some expat Chinese who are critical of the communist party and leader Xi Jinping fear for their lives, despite being Australian residents.  Today, Echo Hui on her exclusive interview for Four Corners with the spy who’s now in Australia and the national security questions raised by her investigation.  Featured:  Echo Hui, Four Corners reporter