Transcript for 'Cartel Land' Explores Deadly Consequences of Illegal Drug Trade
The global market in illicit drugs has turned into modern war. And ground zero is Mexico. Drug cartels battle authorities and each other. Tonight an up-close look the enormous costs of this war as vigilante groups take on the cartels. A story told on the oscar-nominated documentary "Cartel land." Here's ABC's Matt Gutman. Reporter: Brewing in that barrel the stuff of war. It's meth. Cooked by masked and heavily armed men deep inside the Mexican jungle. The cooking process and the shoot-outs that ensue in a war to control the drug trade, just some of the rarely seen images blasted at you in the oscar-nominated documentary "Cartel land." It's a chilling look into Mexico's drug war. A war so brutal, just this week the pope made an emotional plea to Mexico's youth to resist the temptation of the cartels and pray for the victims of this deadly battle. This is war that's happening he country just south of us. War in which 100,000 people have been killed since 2007. This is a car that we're responsible for. Reporter: Filmmaker Matthew Heineman spent nine months in a Mexican state to bring the war home to us. According to the Dea Mexican cartels supply as much as 80% of all meth sold in the U.S. That's why there's been this fight for power in this area. Reporter: And a large portion of it cooked up by the knights templar cartel. Their byproducts are extortion, kidnappings, torture, and murder. The cartel wielded almost complete control for over a decade. So much grief and injustice, so little government action, that citizens decided to fight back. In 2013, organizing themselves into a vigilante group called the alter defenses, or self-defenders. Led by a larger than life small-town doctor, Jose Manuel morales. Heineman was there to capture the heady early days of this movement. Their goal, to take down cartel members one by one. As the movement grows larger and more powerful, Heineman discovers this is not just a story about good against evil -- I came away thinking there is no difference between the knights templar and the defenses. They use the same means, murder, extortion -- There are definitely members of the group that operate that way. But not everyone was like that. Everybody's trying to protect their villages or their towns. What unfortunately took place was power corrupted. Reporter: That evil whippg up increasing violence from which not even the documentarian was immune. Were you ever a target of the cartel? There's countless times when I was surrounded by people, threatened. There's many, many close calls and scary moments. Reporter: The government issued an ultimatum to the vigilantes. Pledge allegiance to the government and enjoy immunity, or go to jail. Fearing prosecution, most surrendered and were rearmed. But morales holds out because he believes the government itself has been corrupted by the cartels. The very institutions that are there to protect them either weren't there, or they were working in collaboration, direct collusion, with the cartels. Reporter: U.s. Authorities say it's widespread corruption that makes this the drug war so difficult to fight. Last July the Mexican government was called into question when narco king man el chapo cauguzman busted out of this prison in Mexico City through an underground tunnel built into his cell, what many experts believed was pulled off with help from the inside. Months later authorities reportedly tracking him to this secret hideout. Seen here this video released by the melks can government. But el chapo outsmarted the Mexican Marines by slipping away through this mirrored wall, designed for this exact moment. It's incredible that right out of that closet and that mirror is this perfectly constructed secret passageway. We're going to go down the stairs here. It led to a tunnel and then the city's drainage system. Hundreds of yards el chapo and his lieutenant crawled through here, you can't even crouch, three feet high, extremely claustrophobic. You can tell why they came out of here looking so feltsdy. He was finally caught and sent back to jail but not without exposing the weaknesses of Mexican law enforcement in the face of the cartels. And they rely on tunnels, not just as escape routes but also as smuggling routes. This is terrifying. But it only has to be comfortable enough to do one thing -- smuggle drugs fast. So far, authorities have uncovered more tn 180 tunnels along the 2,000-mile-long border with Mexico. The cartels smuggle not just underground but over it too. Brazenly muling across the open border. The cartel scouts keep getting away. In "Cartel land" we meet another armed vigilante group fighting on this side of the border. Arizona border recon is led by Tim nailer Foley. Once I learned how the cartels pretty much control both the human smuggling and the drug smuggling, we shifted our primary goal to keep cartel activity out of the country. Reporter: Which is why initially Foley appreciated the order of defense 1,000 miles to the south. They're taking back what is theirs from the cartel and it's nice to see they're standing up and going back at them. Reporter: But "Cartel land" reminds us that power corrupts. The film showing that over time, morales made too many enemies. He was ultimately arrested on gun charges and taken to jail where he has languished for over a year and a half without trial. When he heard "Cartel land" was nominated for an Oscar, morales sent Heineman this audio recording from jail. Translator: I'm grateful for the noble gesture you had in making this documentary movie, that you had to suffer with me daytona in the battles we all endured together. Reporter: As those battles continue, the chefs keep cooking up addiction and sending it northward. At the heart of this is America's voracious appetite for drugs. You know, it's basics of supply and demand. As long as there's a demand for drugs up here, there will be a supply of drugs coming from Mexico and south America. Until that stops all this violence that comes with it won't stop. Reporter: For "Nightline" I'm Matt Gutman in Los Angeles. You can see if "Cartel land" will win the golden statue at the oscars February 28th right here on ABC.
This transcript has been automatically generated and may not be 100% accurate.