A few years ago, a well-regarded national magazine published a cover story, entitled "America's Most Dangerous Gang," giving MS-13 (Mara Salvatrucha) this distinction. In the 1980s, the Los Angeles-based Crips and Blood gangs seemed to be competing for the title.

However, if you consider that the 500 Los Angeles Hispanic gangs outnumbered the combined armies of all the Crips and Blood gangs by more than double; the Southern California Hispanic gangs are united under the umbrella "Sureños;" and that Sureños include the three biggest gangs—Florence 13, 18^th Street and rival Mara Salvatrucha 13 —you might give that title to the Sureños.

In Southern California, the Sureño gangs are the most active criminally, and the most prolific in gang killings by far. The African-American gangs are normally the victims of Sureños in hate-crime incidents, and the Sureños are invading Northern California cities by the hundreds, not vice versa.

The Sureños serve their masters—the Mexican Mafia (known as La Eme, the letter "M" in Spanish) prison gang. This alliance is the most dangerous prison gang and disruptive group combination. They control the majority of the California Department of Corrections facilities. In and out of custody, if one Eme member or Sureño becomes involved in a fight with law enforcement, all Sureños are required to assist the gang member against the police. Any Sureño in the vicinity must assault any other cop or prison staff member in the area. This Eme-Sureño coalition is rapidly gaining footholds in the Federal Bureau of Prisons.

The American media and even law enforcement, unfamiliar with the dynamics of real prison gangs, often try to compare these apples to oranges. Prison gangs are a quantum leap from street gangs , no matter how big or how powerful the street gang may be. Only traditional organized crime and large drug cartels can compare.

The prison gang's power over street gangs was dramatically illustrated in an incident that occurred in November of 1995.

Two years earlier, the Mexican Mafia had issued three edicts to Southern California Hispanic street gangs: Take over drug areas formally controlled by African-American gangs; tax illegal-alien drug dealers operating in Sureño controlled areas; and stop drive-by shootings. This was publically advertised in the newspapers, on radio and on TV as a "Hispanic peace initiative."

It was actually an attempt to reduce collateral casualties in the gang wars that drew unfriendly public attention and heavy police response that was interfering with their lucrative drug business. The gangs were encouraged to continue killing in face-to-face "walk-ups."

But the drive-by tactic was a bad habit that was hard to break for old school Latino cholo gangs. Some young unsophisticated gang members failed to take the Mexican Mafia's edicts seriously. These gangsters became human pin cushions in jail after being arrested by the cops.

The Florence 13 (F-13) gang dates back to the early '50s and dominates a wide geographic area in South Los Angeles. This major Hispanic gang had expanded from its traditional Florence District to the southeastern suburbs of Cudahy, Bell Gardens, Maywood, Bell and Huntington Park. It had become an international, or "transnational," gang that spread across the country (a restaurant in New York bears the gang name) and into Europe, and South America. Florence drug dealers sold multiple kilos and had connections to major drug trafficking organizations in Mexico. But they are also Sureños loyal to the Mexican Mafia.

In October of 1995, Florence gang members Ricardo Perez, 21, Cesar Merino, 21, and Jose Munguia, 20, drove up to a Huntington Park residence. Jose Munguia opened up on the residence with an AK-47 from the vehicle. On the front porch, 11-year-old Erica Izquierdo was swinging on a hammock with her father when she was fatally hit in the head by the AK round. Luis Lopez, 15, and Adrian Garcia, 14, were also struck by the F-13's bullets, but they survived.

Ten days later, Perez and Merino got a visit from a Mexican Mafia member. The Eme member demanded to know just who had fired the fatal shots. Unlike in the American legal system, the two gang members did not have the right to remain silent, or not to incriminate themselves. They quickly ratted out their homeboy Munguia to their demon master.

The Mexican Mafia boss required the death penalty for the drive-by child murder. He made them the classic "offer they could not refuse." They were ordered to murder their own friend and homeboy, or the entire F-13 gang would be on the Mexican Mafia's "green light" murder hit list.

Some say that this mysterious Eme enforcer rode with two young Florencia (Spanish for Florence) members to their homeboy's house. At about 11:30 a.m. on a Saturday, one of the homeboys knocked on the front door and politely asked Jose Munguia's mother if his friend could come out on the porch to speak to him.

When Munguia stepped out on the porch, his two F-13 homeboys executed him with multiple gun shots to his head and body. The family cried in utter disbelief as the two dutiful assassins drove away. They were arrested later that same day, and I was called to testify in their trial. My expert gang testimony involved explaining to the jury what could motivate the suspects to kill their childhood friend in cold blood. After a very emotional plea by the parents, both young gang members were convicted and sentenced to long terms in prison. They are probably on Eme's fast track to Mexican Mafia membership, "putting in work" behind bars, killing for their Eme masters.

No matter which big bad bloody band of barrio bad boys you might be dealing with, I'll bet they are taking their orders from prison-gang inmates. And when one prison gang member can walk with immunity into some street gang's turf and order them to murder one of their own, that's a clue. F-13, 18^th Street and MS-13 all pay taxes to and obey the codes of conduct dictated by the Mexican Mafia.

So ask yourself, who is the most dangerous gang?