WASHINGTON — Federal agents hunting leaders of a multibillion-dollar Mexican drug cartel began their case with crumbs: a fake container of corn chips and a threat scrawled on a Hallmark greeting card.
It took two years of sleuthing before top U.S. law enforcement officials were able to gather in Washington this past week to announce indictments that targeted criminal leaders who oversee mass amounts of cocaine and heroin flowing into U.S. cities.
The case began to take form on a muggy night in Chicago in the summer of 2007, just before the July Fourth holiday, according to law enforcement officials and court documents.
A government informant for the Drug Enforcement Administration wore a recording device to make a small drug buy on the west side of Chicago. Other small developments put investigators on the track of bigger game.
Another break came when a traffic stop caught a man with an illegal gun. He told investigators he got it from a drug dealer because he was scared someone was trying to hurt him and his family.
"Last night when he walked to his car, he found a Hallmark card with a threatening message in it," court documents said the man told investigators.
The next morning, another card, with another threat.
Seeking leniency for the gun charge, the man agreed to cooperate with investigators and bought more guns from the suspected dealer — under DEA surveillance.
And a police stop caught a suspect with a fake "can of Fritos" hiding drugs, according to court papers, and again the suspect agreed to cooperate with investigators. That suspect helped investigators home in on a different Chicago-based drug dealer known as "Fat Mike."
Investigators caught "Fat Mike" talking on the phone about his Mexican supplier, called "Slow Poke."
"Slow Poke," the dealer suspect said, is "real cool" and has a lot of money, according to a transcript of the conversation in court documents.
The evidence they gathered eventually led the agents to begin chasing two bigger Chicago drug suspects, twin brothers Pedro and Margarito Flores, who are now charged with operating a key distribution hub in the Windy City for the Mexican cartel bosses.
Last year, the brothers also found themselves caught in a dispute between warring cartel factions.
U.S. officials say the brothers, who were allegedly bringing about 4,000 pounds of cocaine to Chicago every month, were threatened with violence by each side if they did business with the other.
In Mexico, the two sides have waged a bloody war for control of turf and to fight efforts by Mexico's government to crack down on the drug trade. While Colombian drug dealers once predominated the U.S. supply, law enforcement officials say Mexican crime bosses took over the distribution, causing a significant power shift around 2004.
The growing reach of the cartels has meant an explosion of bloodshed in Mexico, where drug violence has claimed more than 11,000 lives in the past three years.
Many of the killings are the result of battles between rival drug smugglers for lucrative routes into the United States.
Attorney General Eric Holder warned that those same cartels are now "in our own backyards" — and according to court papers are operating in Chicago; Cincinnati and Columbus, Ohio; Detroit; Milwaukee; New York; Philadelphia; Washington; Vancouver, British Columbia; and elsewhere.
Yet one of the most sought-after suspects, Joaquin "El Chapo" Guzman-Loera, has evaded capture for years after escaping from a Mexican prison in 2001.
The new indictments give the government a legal framework to prosecute cartel leaders but will only matter if they can be caught.
U.S. officials insist they are hurting the cartels.
"Every time we target and go after these cartel leaders," said DEA boss Michele Leonhart, "we find out more and more ways to attack them and that's why we continue to do it."