Four Corners: April 15

Monday’s Four Corners episode is “The Discord Leaks,” a PBS Frontline production with The Washington Post.

Four Corners brings you the inside story of one of America’s biggest national security leaks.

The documentary exposes the inner circle — and the young US Air National Guardsman at the centre of it — who leaked classified defence documents on an online chat platform.

Reporters from The Washington Post investigate 21-year-old Jack Teixeira’s motivations, ask why he wasn’t stopped, and examine the role of platforms like Discord.

8.30pm on Monday 15 April on ABC.