One of my TIME colleagues in Mexico, Ioan Grillo, whose book, El Narco: Inside Mexico’s Criminal Insurgency, is being published this month, agrees. “For the Zetas, political murder is done concretely to protect their own business interests inside Mexico,” Grillo told me today. “It’s just not their modus operandi to carry out political murders in the U.S.”

Had Arbabsiar actually been dealing with the Zetas – and not a U.S. Drug Enforcement Administration informant who posed as a Zeta operative – they probably would have conveyed that reality to him fairly quickly. And they would have likely dismissed the $1.5 million that Arbabsiar allegedly offered the D.E.A. informant. The Zetas, after all, are part of a Mexican drug-trafficking, kidnapping and extortion industry that rakes in as much as $40 billion a year. To risk that kind of cash flow by carrying out a five-alarm international hit for a million and a half bucks seems a non-starter. It also seems an organization like the Iranian Revolutionary Guard, for whom the Justice Department says Arbabsiar may have been working, should know better. Arbabsiar, who lives near Mexico in Corpus Christi, Texas, certainly should have been wiser.