The Alfred P Murrah Federal building in Oklahoma city on 19 April 1995.

 The documentary An American Bombing shows how the 1995 act of terror, which killed 168 people, spoke to an increase in US anti-government extremism

An American Bombing tells the story of the single deadliest act of homegrown terrorism against the government in American history. On 19 April 1995 Timothy McVeigh ignited a truck bomb outside the Alfred P Murrah Federal Building in Oklahoma City, killing 168 people, including 19 children.

The documentary recounts the details of that day, the experiences of survivors and victims’ families, the manhunt for the perpetrators and the key moments of the trials. It also digs into the arc of McVeigh, his struggles after serving in the Gulf war and his association with pro-gun, anti-government groups.

Speaking from Blowback Productions in New York, a framed poster for the film Slam visible above a desk behind him, the white-haired Levin admits via Zoom: “Like many people, I accepted what became the popular narrative that this was a lone bomber, disaffected and alienated.

“I didn’t see any connection to the larger movement. which is a direction we went in with this film. A major thrust is to connect McVeigh and this whole tragedy to this anti-government movement, whether you call it white power, neo-Nazi, skinhead, Christian identity, anti-tax.

Levin and co-producer Daphne Pinkerson set about joining the dots. The Turner Diaries, published in 1978, became a bible for the anti-government movement, showing how a small group of insurgents can cause an uprising. It inspired McVeigh and, notably, includes a fictional attack by white supremacists on the US Capitol.More than just a crime story’: the Oklahoma City bombing and a rise in domestic terrorism