An FBI informant described to 10News how the Mexican Mafia controls many of the drug deals that come through the San Diego area each day.The war among drug cartels rages on in Tijuana and Baja California, with the prize being a billion-dollar piece of the action -- moving drugs through San Diego."Cartels come over here, they have to deal with the (Mexican) Mafia," said FBI informant Andrea Gomez.Gomez was a highly placed member of the Mexican Mafia, a gang that formed inside California prisons 30 years ago and has now evolved into a highly organized criminal enterprise."The Mexican Mafia is, put it this way, a United States-run business," said Gomez.Authorities said the Mexican Mafia extracts a 10 percent tax from anyone doing drug business in San Diego and Orange County."I ran San Diego County. I ran it for the Mexican Mafia," said Gomez.Gomez told 10News payment was in either cash or drugs, and anyone who wanted the Mafia's "services" must pay."I would guarantee safe passage," said Gomez.If the tax was paid, the Mafia provided an insurance policy -- no hassles from street gangs, including a particularly deadly group known as MS-13, or surprises from law enforcement the Mafia controls.Gomez said, "When their drugs hit this side, I guarantee no one would rob them. If anyone owed money, the boys would go get them."The Mafia even offered a "delivery service," and Gomez added, "I had 10, 20, 30 people who could get rid of drugs like that (snaps fingers)."Gomez said she worked directly with and for the bosses of the Mexican Mafia, all while she was an FBI informant."They were giving me drugs, drugs, drugs and I was being turned over to the FBI," said Gomez.Everything she learned and everything she touched went to a special FBI investigation known as Operation Keys to the City."I'm talking about pounds of drugs. I'm talking about guns, weapons, assault rifles ," said Gomez.Gomez arranged deals with the cartels but never in Mexico because the FBI did not want her going south of the border."They couldn't go over there. They couldn't follow me over. They were adamant about me not going over," Gomez said.The agency was interested in which cartel, whether it was the Sinaloa gang or Arellano-Felix gang, was doing business with the U.S.-based Mexican Mafia."The Sinaloa, we didn't work with them. We worked with Arellano. Sinaloa was ruthless," said Gomez.Some deals did not always go smoothly, particularly when law enforcement changed its strategies suddenly."We had problems, when they closed down the tunnels, getting the drugs across," said Gomez.When authorities began finding tunnels, Gomez said the Mafia and the Arellano-Felix organization increased their bribery of American border agents."There were locks you could purchase from Border Patrol agents. The lock is what they put on the back of the semis," said Gomez.Gomez referred to the thousands of trucks heading north, passing through the Otay and San Ysidro border crossings."If it goes by another inspection point, they aren't going to touch it. They see the lock and know it's been inspected," said Gomez.As the cartels move drugs into the U.S., their influence, and that of the Mexican Mafia, is spreading."The Arellano-Felix organization reaches across the 50 states. That's what people don't realize," said Gomez.In the local area, control of the Tijuana/San Diego corridor remains an ongoing and dangerous conflict."You are going to keep seeing bodies in San Diego and over the border," said Gomez.Gomez is now in a private prison after the FBI arrested her on allegations of dealing 30 grams of methamphetamines.She remains secluded from other prisoners and awaits her trial date this spring.