The Los Angeles Times wrapped up a four-part series today that offers a rare — and fascinating — look inside Mexico's Sinaloa Cartel, one of the country's largest and most powerful criminal organizations.

The articles spotlight Operation Imperial Emperor, a DEA investigation that provided one of the most complete pictures yet of how drugs move from the cartel's base in Mexico's Sinaloa state to the U.S

The operation, which ended in 2007, led to hundreds of arrests and the seizure of tens of millions of dollars of drugs and cash.

The investigation eventually led to the indictment of Victor Emilio Cazares, a top lieutenant of Sinaloa boss Joaquin "Chapo" Guzman, the most wanted man in Mexico.

It also reinforced a discouraging truth we have noted before: "The cartel's U.S. distribution system was bigger and more resilient than anyone had imagined, a spider web connecting dozens of cities, constantly regenerating and expanding."

Here are the highlights from the series:

The Sinaloa Cartel runs a multimillion dollar drug trafficking operation that stretches from Colombia to the Bronx. Cocaine purchased from South American producers for about $3,600 a pound can be sold for $7,200 in Los Angeles and $9,000 in New York. After transportation costs, one ton of wholesale cocaine can yield $5.4 million.

Unlike the Colombian cartels of the 1990s, the Sinaloa Cartel does not control the distribution system. Cartel bosses allegedly partner with local criminals — everyone from California street gangs to Italian mafiosos, and Dominicans in New York.

The drugs move from Colombia to Mexico, and then across the border into California. The Sinaloa Cartel likes to move the drugs through the Calexico border crossing, an older point of entry that doesn't have the usual border buffer zone, so customs inspectors have a hard time examining cars. The crossing is located in Imperial County, which has one of the nation's highest unemployment rates, making it a great recruiting base for the cartels.

From the border, the drugs travel across the Imperial Valley to the cartel's distribution hub across the greater Los Angeles area. Distribution cells package the cocaine into smaller shipments — between 300 and 600 pounds — and hide it in trucks that crisscross the U.S.

The distribution chain is compartmentalized — the delivery men who drop the drugs off at the staging areas are long gone by the time the trucks get there. All follow orders from a cartel boss in Mexico.

Victor Emilio Cazares, the indicted Sinaloa lieutenant, was allegedly the primary distributor for the Sinaloa Cartel, but "in many ways, he acted more like a vice president of shipping for a U.S. manufacturing firm, obsessing over logistics and cost control."

In Cazares's network, money was sent back to Mexico via his sister, Blanca Cazares, also known as "The Empress," [and one of Mexico's notorious 'narco-novias'], who allegedly controlled currency-changing houses in Tijuana and other border cities where drug money from Southern California was converted into pesos. The cash was divided into parcels of less than $10,000 and deposited in banks along the border.

Cazares's whereabouts are still unknown. New smuggling routes have popped up and Calexico is still one of the main entry points for cocaine along the Mexican border.

The whole LAT series — which is accompanied by excellent infographics— is worth reading. Check it out here >