MEXICO CITY - With his docu-Western "Cartel Land," US filmmaker Matthew Heineman paints a complex picture of vigilante movements in Mexico and the United States that blur the line between "good and evil."
The 32-year-old New Yorker, who won the best director prize at the Sundance independent film festival, had done documentaries about US social issues until he got curious about why civilians were taking up arms across the border.
For nine months, Heineman travelled between Mexico's Wild West-like state of Michoacan and the southwestern US state of Arizona, winning the trust of the men behind the movements.
This access allowed him to film jarring scenes including a methamphetamine laboratory, shootouts, chases, burials and torture rooms.
"In the (US) Western (film) sense, I thought I was telling the story of guys in white shirts versus guys in black hats, which is a Western construct," Heineman told AFP in an interview in Mexico City.
"Over time, I realised that the story was much more complicated, much more gray, and the line between good and evil was much more blurry," he said.
"That fascinated me. And that drove me to keep going down there and try to figure out what was happening," said Heineman, whose film will open in Mexico on Thursday and in the United States on Friday.
The doctor and the war vet
The main protagonists in his documentary are Jose Manuel Mireles, a charismatic doctor and one of the founders of Michoacan's self-defence militias, and Tim "Nailer" Foley, a war-hardened US military veteran whose Arizona Border Recon group tries to stop drugs and illegal migration.
While the two movements operate on the margins of the law and share a common enemy -- drug cartels -- Heineman said they are very different.
"In Mexico, the violence is real. It is visceral. Whereas in Arizona the violence is much more theoretical, it is a fear that the drug war will cross our borders," he said.
The film -- executive produced by Kathryn Bigelow, the Oscar-winning director of "The Hurt Locker" -- is described as a "contemporary Western," though Heineman himself came to realise that the cowboy archetype was hard to find.
"I had no idea where the story was going. Every single trip, every single shoot, the story was changing. It was this roller coaster," he said.
His other documentaries include "Escape Fire: The Fight to Rescue American Healthcare" (2012), about the US health system, and "Our Time" (2009), a look at America's youth.
'Turning into criminals?'
In "Cartel Land," Heineman shows the breakdown of Mexico's vigilante forces, from their rise in 2013 to their internal rivalries and dismantling a year later by the government, amid accusations that they were infiltrated by cartels.
"We won't turn into the criminals that we are fighting, will we?" Mireles is heard saying in the film.
The tall, mustachioed doctor is seen using his fame to woo younger women until his arrest last year on charges of illegal possession of military-grade weapons and drug dealing. His supporters say the case is rife with irregularities and is an attempt to silence him.
The absence and corruption of government institutions, and the corruptible side of the movements, paint a stark picture indeed.
"I hope that the film provokes a really important dialogue both in the US and in Mexico," Heineman said.
"In the US we have to recognise that there is a war that's happening in the country just to the south of us, a country that we share so much history with, and we are somewhat responsible for that war. We are connected to that war. We are consuming the drugs that are the basis for that war," he said.
"In Mexico, I hope that the film shows people a world that they have probably read and know a lot about, but they haven't really totally seen."