Sometimes a new trend identified by the American media is really an old problem that's become so obvious that it can no longer be denied. Suddenly the light switch is turned on, and we see the cockroach infestation. These bugs have been hiding in the dark for a long time.

Mexican drug cartels are now operating deep in the U.S., reports the  Associated Press . They're operating not just in the border areas of Texas, New Mexico, Arizona and California. They're making beach heads in suburban communities near Chicago; Atlanta; Columbus, Ohio; and Louisville, Ky. They've also been active in Indiana, Michigan, Minnesota and Pennsylvania.

Investigative reporters from the Associated Press interviewed dozens of federal agents and local police. They reviewed hundreds of court documents. The results seem to support law enforcement reports of increased cartel presence in numerous non-border cities. Cartel operatives move into tree-lined neighborhoods and appear unremarkable. They try to fit in to the community. Neighbors are often surprised when SWAT teams show up to raid the residence. They watch police cart away large seizures of drugs and weapons.

About 1,700 miles north of the U.S.-Mexico border, the Chicago Crime Commission, a non-governmental agency that tracks crime trends in its region, recently named the Sinaloa Cartel's leader, Joaquin "El Chapo" Guzman , as the city's "Public Enemy No. 1." This title was last held by Al Capone. Unlike Capone, Chapo has probably never set foot in the city. However, the cartel's narcotics have now flooded America's Second City.

This supply of illicit drugs fuels the violent gang turf wars now engulfing Chicago. James O'Grady, the Chicago police commander who oversees narcotics investigations, has said street gang disputes over turf accounted for most of the city's 500 murders in 2012. Jack Riley, the head of the Drug Enforcement Administration's Chicago office, has said the cartel is "probably the most serious threat the United States has faced from organized crime." Riley also argues that the cartels should be seen as an underlying cause of Chicago's disturbingly high murder rate.

Chicago gang cop Joe Sparks has been sending me photographs and news articles of Mexican cartel activity in Chicago for several years. Chicago authorities began seeing that the cartels were putting their own "deputies on the ground" in Chicago two or three years ago, said Art Bilek, executive vice president of the Crime Commission. "Chicago became such a massive market ... it was critical that they had firm control."

Firm control meant that they couldn't continue to rely on their American gang partners—their distributers and enforcers. In order to ensure their continued profits and to prevent skimming by middle men, cartel leaders sent Mexican drug cartel members and even members of their own families to the U.S. to run the business. In 2008, Jose Gonzales-Zavala was sent by the La Familia Cartel to the U.S. to oversee wholesale shipments of cocaine to Illinois, Wisconsin and Indiana. The former taxi cab driver and father of five settled in a middle-class neighborhood in Joliet, southwest of Chicago.

The same Mexican cartel assigned Jorge Guadalupe Ayala-German to provide security for a Chicago-area stash house for $300 a week. He was promised a $35,000 payment once he returned to Mexico. Both men would subsequently be arrested and charged criminally. The wiretap transcripts from law enforcement's electronic surveillance linked them to their Mexican cartel bosses.

To combat the growing problem in Chicago, a joint task force that included 70 federal agents began operating from a new secret location to focus on the point of contact between these suburban-based cartel operatives and the city's street gangs. This is the point where both are most vulnerable to detection. Their meetings can be monitored, and their cell phones tapped.

A massive drug operation run by the La Familia Cartel was discovered in Atlanta's suburban Gwinnett County in 2011. The operational leader, Socorro Hernandez-Rodriguez, has been convicted. In February, Ohio authorities arrested Isaac Eli Perez Neri, who told investigators he was a debt collector for the Sinaloa Cartel.

Once arrested, investigators and prosecutors have had little success in "rolling over" cartel operatives. Mexican cartels have the well-earned reputation in Mexico of terrorist-like murderers. Over 50,000 men, women and children have been slaughtered since the drug wars began. Family members, journalists, and policemen are not spared. Horrific dismemberment and beheadings often intimidate and "send a message" to those who would cross the cartel.

Danny Porter, Gwinnett County's chief prosecutor, told the Associated Press he has tried to entice cartel members to cooperate. Nearly all have declined. Some laughed in his face. "They say, 'We are more scared of them then we are of you. We talk and they boil our family in acid.' Their families are essentially hostages."

Here's the part that irks me most. So far, cartels don't appear to be directly responsible for a large number of murders in the U.S. Before I retired in 2004, Mexican nationals in Los Angeles were murdering as many people (as many as 600 a year) as the prolific gangs. Many of these murders remain unsolved. They haven't been identified as cartel-related cases because professional hit men make the hit and then quickly return to Mexico. Fear of the cartels keeps witnesses from coming forward and identifying the individuals involved. I imagine that many murders in non-border cities haven't been identified as cartel-driven violence. Nobody is gathering these statistics.

In 2008, U.S. cities reported a cartel presence in 230 American communities. By 2011, that number had climbed to 1,200. In my opinion, the Mexican cartel presence can be found in every major U.S. city and most American suburbs where drug and human trafficking flourishes. If you have a large illegal immigrant population, you have cartel activity.