There is a crisis at the border. Draconian decisions like the zero tolerance policy (which led to the separation of migrant families and horrifying accounts of kids in cages) have made Border Patrol agents key players in a national debate about U.S. immigration. A new documentary produced by PBS’s Frontline series focuses on El Paso, Texas. It’s where many of these policies were first piloted by, as audiences will see, agents who understood that what they were doing was inhumane. They claimed to just be following orders. “I mean, none of us were happy about it,” says Wesley Farris, a high-ranking officer with El Paso’s Border Patrol Union, in the doc. “But everybody around me was just doing exactly what … We were all told to do this.”

Produced by Marcela Gaviria, Targeting El Paso is described by Frontline as an investigation into “how the border city that’s been called the Ellis Island of the Southwest became a testing ground for some of President Donald Trump’s most controversial immigration policies, a subject of his anti-immigrant rhetoric, the site of a surge of migrant families crossing the border — and, on August 3 of last year, the target of a white supremacist with an assault rifle.”

Featuring interviews with current and former officials, Border Patrol agents, advocates and immigrants — including a young girl who was separated from her father for 11 days — the doc puts viewers at the epicenter of what’s become a humanitarian crisis at the border. Shot and edited with the journalistic rigor of PBS’ long-running doc series — prepare yourself for informational voice-overs, one-on-one interviews and many an establishing shot of ICE detention centers — Targeting El Paso should be both eye-opening for those wanting on-the-ground accounts and enraging for those who will be hearing these kinds of stories for the first time.

Frontline: Targeting El Paso is now streaming over at PBS.org.