And authorities said they did it undeterred by keeping it simple.
Family members lived humbly, with underlings distributing the drugs in open view at parking lots of 99 Cents stores, Food 4 Less supermarkets, Home Depots and McDonald's restaurants. At these bustling locations, men inconspicuously trading brown shopping bags filled with heroin didn't seem out of place.
They communicated using an Indian language from their home village -- initially stumping investigators who listened to their exchanges on wiretaps.
"The language -- that stalled us," said Larry Zimmerman, the L.A. County Sheriff's Department's lead detective on the case. They finally identified it as Mixteco Bajo, one of the main Indian languages in the state of Oaxaca, and brought in an interpreter.
On Tuesday, federal and local authorities arrested 48 members of the Mendoza family in raids at 38 residences and businesses that began before dawn and lasted into the afternoon.
The Mendoza clan allegedly sold 15 to 20 pounds of heroin every week -- generating roughly $2 million a month in profits. Much of the money was sent back to Mexico, authorities said.
The arrest offers a window into how heroin from Mexico makes its way north and into Southern California -- relying largely on a network strengthened by family ties.
It shows "how heroin initially controlled by [Mexican] drug cartels makes its way into the U.S., into the hands of gang members across the Los Angeles region," U.S. Atty. Thomas P. O'Brien said.
O'Brien said the defendants in the case were indicted on charges of conspiracy to possess and distribute heroin, among other charges. If convicted, they face 10 years to life in federal prison. The federal indictment of the Mendoza clan showed that the group shunned the ostentatious trappings normally associated with high-end drug traffickers.
The clan allegedly used Ford, Honda and Pontiac vehicles. They stored the heroin in the cars -- hiding it in engine blocks, gas tanks, steering columns, air vents and dashboards. Despite the hefty drug profits, family members lived in modest homes in suburbs such as Montebello.
The seven-month investigation centered around Ramon Narciso Morales-Mendoza, the alleged clan leader. Earlier this year, detectives found $10,500 hidden in the compartment of his car designed to hold the air bag, according to a federal affidavit. (He and other family members could not be reached for comment Tuesday).
On wiretaps, members of the Mendoza clan referred to the drug as "salsa," "burrito," "taco" and "shirts." In safe houses, including one in the city of Commerce, the smugglers would cut the black-tar heroin with lactose using a coffee grinder, according to the affidavit.
Clan members would then break the heroin into quarter-gram amounts and place them in small multi-colored balloons and bunch them together in large plastic or paper bags.
The bags were then distributed to 11 street gangs, mostly in the East Los Angeles area, and other vendors. The gang members would sell the heroin to users from San Diego to Santa Barbara, according to the federal affidavit.
Each week, the network's heroin was broken down into about 150,000 street doses, officials said.
"That's enough to supply thousands of people every week," said Tim Landrum, agent in charge of the Los Angeles office of the Drug Enforcement Administration.
At times, the network provided Christmas bonuses in the form of free heroin to those who sold for them, authorities said.
"One customer we arrested came from Santa Barbara," Zimmerman said. "He said it's the best heroin there is. He'd buy a balloon for $5 in L.A. and sell it for $40 in Santa Barbara."