The numbers are hard to comprehend - thousands of people killed, tons of drugs seized and billions of dollars exchanging hands. And Iowa is right in the middle of the Mexican drug cartels' distribution network.
It's the middle of the night in Pinal County, Arizona. Just as he does on every mission, Lt. Matthew Thomas, with the Pinal County Sheriff's Office, makes a mental checklist.
"You're getting your stuff ready, getting into game time mode."
His team plans to raid two locations tonight. They're stash houses, used to store drugs awaiting distribution through a nationwide network.
"Sheriff's Office, search warrant," one agent yells as he bangs on the window.
Lt. Thomas and his team take three people into custody and uncover dozens of bundles of drugs in a pickup parked outside. There are more drugs inside the stash house, along with a shrine of saints. Some are legitimate saints, like the Virgin Mary. Others, like Saint Jesus Malverde are called "narco saints." Malverde is considered the patron saint of the illegal drug trade. Traffickers pray to him for the safe delivery of their loads.
Lt. Thomas carries a picture of Malverde in his patrol car. It's a souvenir from his days undercover, when he had to convince dealers he was one of their own.
"Every time you walk out the door you always wonder is today the day," says Lt. Thomas. "Who do I want carrying my casket? What type of funeral do I want?"
He's developed a warrior mentality. You understand why, when he explains how the drug cartel has infiltrated the area.
"They've got bad guys in their communities that dress like good guys, act like good guys, but indeed they're working for the opposition."
There are bad guys in the mountains and on the desert floor. The person driving a tractor in a field by the road may only be posing as a ranch hand.
"That guy may be employed by the cartel on the side and has a cell or radio and as soon as I pass by and he recognizes me as law enforcement he just makes a phone call in and says 'Law enforcement is at this location, that location.'"
As we approach a known "drop site," it become clear, the cartels are watching us as much as we are watching them.
Lt. Thomas instructs us to stay by the car as he checks out the location. He tells us to radio dispatch with our location, should something go wrong.
"If you want to film anything you can get out, but just stay at the car, just in case."
After giving us the all clear, Lt. Thomas shows us evidence smugglers are using this old ranch house to transfer drugs.
"There's been activity here in at least week, that's for sure." Lt. Thomas points to a recent fire, "There's no wind or water damage, so that's fairly recent, like in the last few days."
The smugglers are called mules. They walk day and night through the desert, carrying as much as 50 pounds of pot, heroin, meth or cocaine in home-made burlap back-packs.
"For us, that's indicative of drug smuggling, specifically."
When they reach the drop site, the mules drop everything - their drugs, their outer layers of clothing, their water bottles - and wait. They wait for word from the next person in the drug cartel chain of command. Another tell-tale sign that this is a drop site - booties made out of carpet. The smugglers fasten them to their shoes to disguise their footprints.
"They'll clean up. They'll rest. They'll eat. They'll let their bosses know, 'Hey were at the pick-up point.' Then a vehicle will come in and they'll load the vehicle up."
Another vehicle will pick up the people.
"Then they'll shoot them back south and they do it all over again."
Some mules, referred to as "quitters," rely on law enforcement for a ride home. They'll walk to the nearest interstate or highway and simply surrender, knowing police will transport them back to Mexico. For some quitters, it's a short walk.
Lt. Thomas takes us to a drop site directly be an Interstate 8 overpass. He says as lookouts watch for the law, the smugglers load the drugs into a transport vehicle pulled on the side of one of the busiest roads in Arizona.
"They're like a pit crew. Within five to ten seconds they'll have that car loaded up with dope," says Lt. Thomas. "Then they're on the interstate and they're shooting out."
The fingers of the Mexican drug cartels reach across the country. Before they even cross the border, the drugs are brokered out to dealers, located in cities like Phoenix, San Diego, Denver and Dallas. They then travel north and northeast along the nation's interstate system. I-80 and I-35 are two major pipelines, leading directly to Iowa.