NEW YORK (Reuters) - The idea of Mexican drug cartels cooperating with Iranian plotters to carry out bombings and murders in the United States may be far-fetched.
That is because the alleged plan by Iranian-American suspect Manssor Arbabsiar and a co-defendant to use a Mexican gang to kill the Saudi ambassador in Washington may have been as much conceived through a sting operation by the U.S. Drug Enforcement Administration (DEA) as hatched by a branch of Iran's Islamic Revolutionary Guard Corps.
U.S. authorities generally do not believe that any Mexican drug cartel would currently consider leading attacks of that scope within the United States.
Had Arbabsiar contacted an actual cartel member rather than a DEA agent posing as one, he might eventually have been killed, given the risks to the cartel of such an operation, according to a law enforcement official, who declined to be identified because of a lack of authorization to speak publicly on the matter.
The case is as notable for the increasing involvement of America's anti-drug agency in national security investigations, including a number of such stings in recent years, as a sign of any new threat from Mexico, security experts and U.S. officials say.
"If you are a member of organized crime ... you are there for a business, your business is not killing people, your business is to transport humans, to sell illegal goods, that's your line of business. Assassination attempts are not what they do for a living," said Alberto Islas, from security consultancy Risk Evaluation.
Some officials do point to an increase in the number of terrorism-related cases involving the DEA as proof that those seeking to attack Americans or those on American soil have contacts with drug smuggling groups.
The scenario of "a state-sponsored organization planning a terrorist attack, leveraging drug cartels to perpetrate an attack that has a geopolitical impact... is precisely why the DEA really has been thrust into the thornier issues, and right into that space," said Juan Zarate, who was a national security adviser to former president George W. Bush.
Still, that may be more of a scenario than a clear threat.
It was a DEA informant who tipped the agency about the suspected plot of two Iranian agents trying to hire someone who had experience with explosives to assassinate the Saudi ambassador, according to court documents released on Tuesday.
Alarmed and intrigued at what they heard about a possible wider plot involving Iranians with government connections, DEA and FBI officers launched an elaborate investigation.
But it seems to have been the informant, likely under instructions from his handlers, who decided to pose as an explosives-savvy member of the Zetas, a Mexican drug gang.
The increased involvement of the DEA in national security cases stems largely from its international network of informants, experts said, and the agency's decades of experience maneuvering abroad, particularly in Latin America.
The involvement of the DEA "does not necessarily mean that more terrorism cases now involve drugs, but that the agency's expertise, breadth and know-how are being used more and more in national security cases," said Karen Greenberg, director of the Center on National Security at Fordham University School of Law.
"While the DEA's role might not be visible when the details of a case are spelled out in an indictment, it has played an increasing role in investigations and arrests in terrorism-related cases," Greenberg said.
Last year, for example, Manhattan U.S. Attorney Preet Bharara combined his office's Terrorism and National Security Unit with its Narcotics Trafficking Unit.
Three months ago, when announcing drug and terrorism charges against four men arrested in two separate DEA sting operations, Bharara cited the growing nexus between drug trafficking and terrorism. The men were allegedly connected to Afghanistan's Taliban and the militant Lebanese group Hezbollah.
The combined drug and terrorism unit is handling Arbabsiar's prosecution. This may partially explain why he, and the four men charged in July, were brought to New York to face charges.
The case of suspected Russian arms dealer Viktor Bout, who is now on trial in New York, has some similarities to the suspected Arbabsiar plot.
Bout was nabbed in Bangkok in 2008 in a DEA-led operation where U.S. informants posed as arms buyers from the Revolutionary Armed Forces of Colombia, known as FARC.
He is fighting charges of conspiring to kill U.S. nationals and conspiring to provide help to a terrorist group. At the opening of his trial on Wednesday, he argued that he never intended to provide the weapons the supposed FARC commanders offered to buy from him. His case was made infamous after he was dubbed the "Merchant of Death" in a book about him.
Washington classifies the FARC, a Marxist-inspired guerrilla army, as a terrorist organization and says it is deeply involved in the cocaine trade.
Both the Arbabsiar and Bout cases were sting operations involving DEA sources posing as members of a violent drug smuggling group.
According to the criminal complaint unsealed on Tuesday, Arbabsiar approached an individual who eventually identified himself as a member of the Zetas cartel, and offered to pay him to kill Saudi Ambassador Adel al-Jubeir.
U.S. officials say Arbabsiar was following orders by the Islamic Revolutionary Guard Corps, the guardian of Iran's 32-year-old revolution, and the Quds force, its covert, operational arm.
Arbabsiar is in custody. His attorney, Sabrina Shroff, has said that if her client was indicted, he would plead not guilty. She declined to comment.
A second Iranian man, Gholam Shakuri, was also accused in the plot and is currently at large.
Another case experts point to as a key example of DEA-led investigations is the arrest and prosecution of Syrian native Monzer Al-Kassar in 2008.
Kassar, a longtime resident of Spain known as the "Prince of Marbella," was arrested after he agreed to sell weapons to DEA informants posing as member of FARC.
The informants told Kassar they intended to use the weapons against U.S. forces in Colombia. Kassar was convicted at trial in Manhattan federal court in 2009 and is now serving a 30-year prison term.
Reporting by Basil Katz in New York. Additional reporting by Krista Hughes in Mexico City. Editing by Martin Howell