A Border Patrol agent checks vehicles for illegal immigrants and contraband at a roadside checkpoint in this June 1, 2010 file photo near Sasabe, Ari. (Scott Olson/Getty Images)
A corrupt U.S. border agent sitting in a federal prison cell is offering a chilling view of the Mexican drug cartels whose drug shipments he protected for years in return for hefty bribes.
He is so terrified of the cartel's famous vicious streak that he fears for his own life -- and the lives of his family -- if he is identified as speaking to ABC News. He depicts a dangerously paranoid crime organization that has spies throughout U.S. law enforcement.
To illustrate the cartel's pervasive reach, he said he got his introduction to them through an American cop. From there the former border patrol agent was convicted of shepherding cartel vehicles loaded with drugs safely over the border. Prosecutors say he profited handsomely, being paid $4,000 per car and $6,000 to escort vans - in addition to a $10,000 retainer fee.
According to the indictment, the agent's run came to an end after he unknowingly offered his services to other drug dealers-- who were undercover FBI agents. In the sting, the agent assisted the undercover agents in smuggling a huge shipment of cocaine into the U.S. He largely concedes the facts of the case against him, but insists there is more to his story.
U.S. Border Agents Seduced By Mexican Drug Cartels
"First and foremost, I was a USBP agent. But when the threat is real and it's on your own family... it turns into a whole new ball game," he said in a series of emails in which he answered questions put to him by ABC News.
"Regardless of my crime, I served my country and my community to the best of my abilities (above and beyond)... no one will ever take that away from me," he wrote.
The disgraced agent said the cartel was more powerful than the U.S. government and overrode his oath as a law enforcement officer.
"In my opinion they have unlimited power..they have informants of all kinds, good and bad," he said. "They have informants in the city level, county level and, from what they claim, federal."
"At the time I was just thinking of a possible life and death situation and DEATH had better odds than I had.... Until you are faced with a situation like mine... no one can really say what they could have done."
He said he first reached out to the cartels because it was a form of security. If he helped the cartels, he could keep his drug-dealing brothers in Mexico safe.
"Of course I knew I was taking a big risk. It went against everything I believed in and worked hard for," the agent said. "Yes, I was terrified of getting caught, but more terrified of losing my brothers."
At a softball game, the police officer introduced him to a man who had connections in the part of Mexico where his brothers' lives were being threatened and the guard believed they might be able to help his brothers if he worked with them. He did not know, however, that once he got involved with this dangerous world, it would be impossible to get out.
He also did not identify which of the Mexican drug cartels he dealt with.
"At first I was doing it for free because I wanted to get my brother's problems taken care of, but then I got whatever they gave me," he said. "They wouldn't take no for an answer and I had to play along."
In a world where suspicion could be fatal, the former guard said he had to accept the bribes in order to curb the cartel's paranoia.
"The money was not something I could say no to...because I had to make them believe that I was doing all I could to be on their good side," he wrote.
He communicated with the drug trafficking organizations by radio and sometimes in person, which he said was "scary and stressful."
Mexico Cartel Extends Its Menace to U.S. Prison
Trusting no one, he believed he was under constant surveillance and described a situation where he met a woman at a safe house. The meeting came right after he and other officers had been warned that the cartels were using women to try to get agents into Mexico in order to kill them.
When the first person he met at a safe house was a woman, he was terrified. The cartel told him the woman was there for his "personal enjoyment," but he suspected the real purposed was to get him naked so that they could see that he was not wired.
He can't stop thinking about what he has done and can't stop worrying about the cartel, even behind bars.
"I worry a lot because I know [their] method of operation and in what areas [they operate]," the guard wrote. "In other words, I believe that they think that I know too much."
He isn't just afraid for himself.
"I worry about my family because they are living in border towns and in Mexico," he said. "I fear for their lives because I believe that those people are just waiting for me to say the wrong thing about them or someone in particular."
The Mexican drug cartel industry has an estimated worth of more than $15 billion and continues to grow. Violence has escalated in the industry and battles involving automatic weapons and grenades are common. Over 34,000 people have been killed in Mexican drug wars over the past four years.
In a disturbing trend, new figures show 122 current or former U.S. federal agents and employees of the Customs and Border Protection agency have been arrested or indicted for corruption since October 2004. It's not just for money, some agents are accepting payment from the cartels in the form of sexual favors.
Just last week, a police officer, a state trooper and three TSA officers in Florida and Connecticut were among 20 arrested for allegedly running an interstate drug ring. "
"It will get worse before it gets better," the former agent predicted.
Even though the agent describes prison life as "a terrible experience," he believes he did the best he could for the circumstances he was in.
"I knew that what I was doing was wrong. But, at the time, I thought I had no other options," he said. "It's easy to find an answer right now, but back then...it was a nightmare."