Mexican drug cartel Los Zetas is wanted in many respects -- Iran wants to hire gang members to kill the Saudi Ambassador, Mexican police want to capture them.

Part of the recently foiled Iran terror plot to assassinate Saudi Arabia's ambassador to the United States, an alleged Iranian operative in Texas met who he thought was a member of Los Zetas, one of Mexico's many deadly and powerful drug rings. Manssor Arbabsiar offered $1.5 million to the Zetas to blow up the Saudi and Israeli embassies in Washington D.C. and possibly Argentina, according to The Guardian.

The Zetas member turned out to be a Drug Enforcement Administration informant, who was taping the meetings and had Arbabsiar arrested in New York this month.

Iran's choice of cartels was an appropriate one. Not only have Los Zetas clearly become the biggest, most serious threat to the nation's security, according Mexican scholar Raul Benitez, the D.E.A. considers them the most technologically advanced, sophisticated and violent of these paramilitary enforcement groups in Mexico.

For this reason, they are one of the principal targets of President Felipe Calderon's war on drugs, although they have been one of the hardest gangs to stop.

Mexico's Ministry of Defense said Thursday that a yet-to=be named Zetas leader had been captured in Saltillo. The man is said to be the principal manager of the gang in in the states of Coahuila, Nuevo Leon and Tamaulipas, according to CNN.

It is the first significant arrest since the casino arson in Monterrey that killed 52 people. The Zetas have been blamed for the event, which was likely a retaliatory attack against casino owner who refused to pay the cartel protection money.  

Mexican police have had better luck arresting the leaders of the La Familia and La Linea gangs. In June, La Linea's Marco Antonio Guzman Zuniga, nicknamed El Brad Pitt was apprehended for a car bombing and La Familia's Jose de Jesus Mendez Vargas, also known as El Chango or The Monkey, was arrested for murder and extortion.

Authorities also captured Oscar Garcia Montoya -- nicknamed El Compayito, which is the name of a popular hand-puppet in Mexico -- who is assumed to be the leader of the dangerous Mano con Ojos or Hand with Eyes cartel. Garcia admitted to taking part personally in 300 executions, and ordering another 300, according to prosecutors.

The drug war in Mexico, which has sent entire police forces fleeing from cities, has only escalated in recent years, despite the high-profile arrests. Since President Calderon's inauguration in 2006, the drug-cartel related death toll has skyrocketed to more than 41,000 -- more casualties than some international wars.

Los Zetas have time and again proven to be unfathomably ruthless. The cartel was founded by 30 Mexican Special Forces deserters who conscribed a number of Guatemalan Kaibiles, the special operations force responsible for a number of atrocities during that Central American country's civil war.

The training given to new members has been compared to Green Beret training in the United States, proof that Los Zetas regards militancy -- necessary in territorial battles with rival cartels -- nearly as important as drug trafficking. They have also been known to recruit teenagers, including a 13 and a 16-year-old girl who were trained to be an assassins.

Like most of Mexico's cartels, Los Zetas use violence as a means of intimidation, displaying mutilated bodies in public areas as warnings against would-be police informers or anyone thinking of decrying the group.

In September, two people were tortured then hanged from a bridge in Nuevo Laredo for tweeting disparaging messages about drug cartels.

Attached to the bodies were two signs, one of which read This happens for... denouncing, according to CNN. One of the notes also had the names of two blogs, Al Rojo Vivo and Blog del Narco. The notes were signed with a Z, an oft-used Zetas signature.

A week later, a journalist in Nueveo Laredo named Marisol Marcia Castaneda was decapitated in retaliation for posts she made on a social media network, according to authorities.

Traditional media outlets are as frightened of drug gang retaliations as many citizens, and newspapers often censure their own reports to downplay cartel crimes. This places the reporting burden on bloggers, and now, Twitter users, and it is no surprise that Castaneda posted her comments on the Nuevo Laredo Live Web site and not in the Mexican newspaper Primera Hora.

Nuevo Laredo en Vivo and social networking sites, I'm The Laredo Girl, and I'm here because of my reports, and yours, a message left on Castaneda's body read. For those who don't want to believe, this happened to me because of my actions, for believing in the army and the navy. Thank you for your attention, respectfully, Laredo Girl...ZZZZ.

Castaneda was the tenth journalist killed in Mexico this year and the 74th since 2000, according to Mexico's Human Rights Commission.

President Calderon has vowed to continue the fight against Los Zetas and all of Mexico's drug cartels.

It is evident that we are not facing common criminals. We are facing true terrorists who have surpassed not only the limits of the law but basic common sense and respect for life, Calderon said in a speech last month.

The only way to beat this cancer is for this strategy to persevere, the president added.

While Calderon is making some progress, each big-name capture creates new challenges. When one cartel leader is arrested or killed (often in shoot-outs with the police) a rift forms in that cartel. In many instances, a fight for power between two deputies can leave hundreds dead in just a short time, and thousands dead in the long term as rival gangs battle for turf.

At the current pace, Mexico's drug war appears to be far from over. As police make arrests and new drug lords take old leaders' places, the game continues. And the arrest of Iranian terror suspect Arbabsiar again proves how the Zetas name is ubiquitous with violence, money and power, and will be for a long time to come.