JEFFREY BROWN: Next, a report on who's behind the lucrative marijuana farming business in California.
The Center for Investigative Reporting and KQED San Francisco have been looking into that issue for a year and jointly produced this story for the NewsHour.
Their reporter is Michael Montgomery.
MICHAEL MONTGOMERY, KQED: Marijuana is a cash crop in California. Last year, local and federal authorities seized some seven million illegally grown plants, much of it cultivated on national forests and parks like Yosemite.
Police say the growers are no longer just local hippies. Increasingly, they are armed traffickers ready to confront whoever comes their way.
Mendocino County Sheriff Tom Allman says that's why his deputies are training in new tactics, to capture more growers and disrupt their trade networks.
TOM ALLMAN, Mendocino County, Calif., sheriff: We're at a fork in the road, and if we don't make an aggressive push right now to take back some of our public lands, then we may get to the point of no return.
MICHAEL MONTGOMERY: And more and more, that battle to take back the land turns violent.
LT. RUSTY NOE, Mendocino County, Calif., Sheriff's Department: This was found in a garden.
MICHAEL MONTGOMERY: Last year, Mendocino County saw an unprecedented number of armed confrontations, many with Mexican nationals with suspected links to drug gangs across the border.
LT. RUSTY NOE: We had particular information that there were violent cartel-type Mexican grows up in this remote part of the northern county. As our SWAT team was clearing through one of the gardens, they came down a real narrow trail in the brush. And it just opened up into a camp, with about seven people in it.
MICHAEL MONTGOMERY: One of the seven was this man, Mariano Fernandez.
LT. RUSTY NOE: He had AK-47-type rifle and a handgun, and actually pointed it and tried to get a round off at the SWAT team. And they, of course, engaged and took his life.
MICHAEL MONTGOMERY: Lt. Rusty Noe says the high-powered weapons and large quantity of pot plants recovered at the scene indicate the operation was the work of a large criminal organization.
And Sheriff Allman says the Fernandez case is part of a wider pattern. A month later, his men were involved in another shooting, leaving Angel Farias, also from Mexico, dead.
TOM ALLMAN: I have had people come to me and say, my family has hunted in the Mendocino National Forest for five generations, and we don't go there anymore because every time we go there, we hear shots being fired around, or people have literally walked into our hunting camp and said, get out of here.
MICHAEL MONTGOMERY: But Fernandez's widow, Jessica, who grew up in Mendocino, says the cops overreacted. Mariano was just doing what everyone else does in these parts of California.
JESSICA WAGGONER, widow: Mariano didn't have any ties at all with cartel or gang or anybody but to make money for his family. He was up there doing it by himself. He is not involved with any of that. And neither are any of the other guys that he was with.
MICHAEL MONTGOMERY: Ron Brooks, who leads a federally-funded drug task force in Northern California, doubts that. He says the scale and sophistication of the marijuana growing operations point to something more sinister.
RON BROOKS, Northern California High Intensity Drug Trafficking Area: It is not just the grows. There's got to be a network. That means facilitation of stash houses, of communications, people that rent the cell phones, people that drive the trucks, people that sell this marijuana at the wholesale and retail level, people that get the money bulk transferred back to Mexico, which is where the command-and-control is for many of these organizations. You're talking about a very big organization.
MICHAEL MONTGOMERY: This man, who asked us to conceal his identity, has grown millions of dollars worth of marijuana in California. He became an informant for law enforcement after he was arrested. He says he originally came here from Michoacan, Mexico, to work on illegal pot farms five years ago.
MARIJUANA GROWER (through translator): What you can earn here is 20 times more than Mexico.
MICHAEL MONTGOMERY: He started out as a lunchero, a lunch man. That's a kind of foreman who is hired by a boss to deliver food and fertilizer, often to many sites at the same time.
MARIJUANA GROWER (through translator): I have known other people who have had one lunchero for eight or 10 pot grow sites. But I have known other people who have 25 or 30 pot grow sites.
MICHAEL MONTGOMERY: Since the use of the land is free, so long as you don't get caught, the man says the profit margins are huge.
MARIJUANA GROWER (through translator): You spend about $15,000 to begin a garden. If the land is good, you will get 800 pounds, $200,000 to $300,000.
MICHAEL MONTGOMERY: And he says it's not just the money. It's safer to grow pot in California, even if you get caught.
MARIJUANA GROWER (through translator): In Mexico, you get five years in jail and they break both your feet, both of your hands and sometimes knock out your teeth. So, six months here in the U.S. in jail, compared to Mexico, is nothing.
MICHAEL MONTGOMERY: National Marijuana Policy Coordinator Tommy LaNier says the dangers in Mexico are driving more growers north.
TOMMY LANIER, National Marijuana Policy coordinator: A lot of those people are afraid that they're going to be targets themselves in Mexico. So they figured out that it's easier to come to the U.S., although they bring their same type of attitudes, but they can grow a lot of marijuana. They know how to smuggle in aliens. They have all those networks already set up.
MAN: That water supply goes all the way down to where the plants are to water the plants.
MICHAEL MONTGOMERY: Last month, Sheriff Allman spearheaded the biggest series of pot raids in county history, focusing on the Mendocino National Forest.
So far, there have been 100 arrests and federal indictments against at least 10 Mexican nationals. Authorities say they are investigating links to gangs across the border. But our informant tells us that could be difficult. He says these giant farm operations are financed by Mexican money, but they're not directly controlled by the big cartels, and neither are the workers on the ground.
MARIJUANA GROWER (through translator): The growers are not involved with the drug cartels or with criminal bands. They're just people with families. They just come to grow for a season or two and then return to Mexico.
MICHAEL MONTGOMERY: So, the Mexican cartels that we hear so much about, the La Familia or the Juarez cartel, you are saying they are not here in the pot fields of California?
MARIJUANA GROWER (through translator): No. They only have their people who buy and sell marijuana.
MICHAEL MONTGOMERY: The man explains that while cartel operatives aren't in the marijuana fields themselves, growers still rely on their networks to move the large quantities of pot produced in California.
MARIJUANA GROWER (through translator): All of the Mexican cartels have people in the country. La Familia, cartels from Juarez, the Zetas, they all have people in the United States. The cartels know what to do with the drugs. They carry it to another state or a city and distribute it. That's what they do.
MICHAEL MONTGOMERY: For Sheriff Allman, this means that most of the people the cops arrest are just field workers, but, he says, they're also the supply chain for an organized criminal network.
TOM ALLMAN: I am surely not picking on anybody because of their ethnicity. I am picking on people because of their actions. And the actions of the drug trafficking organizations have harmed my county. And my job as sheriff is to do everything I can to stop it. And that's what we are doing this summer.
MICHAEL MONTGOMERY: But until law enforcement operations reach up the distribution chain, new suppliers will inevitably continue to stream in to Mendocino to feed the growing demand for California marijuana around the United States.
GWEN IFILL: A recent string of arrests in Michigan, Ohio, Utah and Illinois captured many Californians, all with large hauls of marijuana.