CIUDAD JUAREZ, Mexico — A drug gang that carried out the first successful car bombing against Mexican security forces likely used an industrial explosive that organized crime gangs in the past have stolen from private companies, a U.S. official said Monday.
The assailants apparently used Tovex, a water gel explosive commonly used as a replacement for dynamite in mining and other industrial activities, said the U.S. official, who is familiar with the investigation but spoke on condition of anonymity because the official was not authorized to discuss the Mexican-led investigation.
The U.S. official had no other details on how the bomb was constructed, and Mexican officials declined to comment.
The car bomb killed three people — including a federal police officer — Thursday in the border city of Ciudad Juarez, and introduced a new threat in Mexico's drug war. Mexican authorities say the assailants lured police and paramedics to the scene through an elaborate ruse seemingly taken out of an Al-Qaida playbook.
A street gang tied to the Juarez cartel dressed a bound, wounded man in a police uniform, then called in a false report of an officer shot at an intersection. They waited until the authorities were in place to detonate the bomb.
U.S. State Department spokesman P.J. Crowley said the car bomb "may represent a different tactic."
"Unfortunately, these drug cartels, they have an enormous amount of resources at their disposal. They can buy any kind of capability they want. But we are determined, working with Mexico, to do everything in our power to reduce this violence that affects not only the Mexican people, but our own," Crowley told a news conference Monday.
A graffiti message scrawled on a wall Monday threatened more attacks in the city across the border from El Paso, Texas. The message directed its threat at the FBI and the U.S. Drug Enforcement Administration, demanding an investigation of Mexican law enforcement officials who "support the Sinaloa cartel."
The Sinaloa cartel — one of the world's most powerful drug-trafficking organizations — has been battling the Juarez cartel for control of Ciudad Juarez in a 2-year-old war that has converted the city into one of the world's deadliest.
Messages that presumed drug-gang members have scrawled on walls and banners and attached to the bodies of their victims frequently accuse Mexican federal forces of protecting the Sinaloa cartel, a charge President Felipe Calderon's administration vehemently denies.
Monday's graffiti message said there would be another car bomb unless "corrupt federal" officials are arrested within 15 days. There was no way to verify the authenticity of the message.
The FBI and the U.S. Bureau of Alcohol, Firearms and Explosives are aiding the Mexicans in the car bomb investigation, officials from those agencies have said.
"This is a whole new level" of aggression from drug gangs, said Tony Payan, a political analyst and expert in Mexico's effort to combat drug cartels. "When you compare it to terrorism as it is traditionally understood, there are some similarities. The modus operandi was definitely of a terrorist attack. It was designed to instill fear in the police and the general population."
Payan added that the Mexican government was too quick to dismiss the possibility that the motive behind the attack was political.
"When you state purposefully that your goal is to intimidate the police and scare the population it means that you intend to drive an even wider wedge between the government and the government's popular support for the war on drugs," he said.
The day after the bombing, Mexican Attorney General Arturo Chavez insisted there was no evidence of "narcoterrorism" in Mexico or any ideological motive behind the attack. On Monday, officials from his office said they could provide no new information on the ongoing investigation.
Brig. Gen. Eduardo Zarate, the commander of the regional military zone, has said as much as 22 pounds (10 kilograms) of explosives might have been used in the car bomb attack. He said last week that batteries and a mobile phone found at the scene suggested it was remotely detonated.
Mexico's powerful drug cartels have long been experimenting with explosives. In the northern state of Durango in 2009, more than a dozen masked gunmen stole 900 cartridges of Tovex water gel explosives from a warehouse run by the U.S.-based Austin Powder Company. Mexican authorities recovered the stolen material, but the theft underscored how easy it can be to get explosive material in the country, where armed men also have attacked transport vehicles carrying such substances.
The ATF has helped investigate several events involving improvised explosive devices around Mexico, including a roadside bomb in March at a gas station in the northern state of Nuevo Leon. That bomb, which didn't injure anyone, consisted of two large cylinders filled with nails and possibly black powder, another substance that is readily available on the black market.
Mexico's drug violence has killed nearly 25,000 people since December 2006, when Calderon deployed thousands of troops and federal police to fight the cartels in their strongholds.
The government announced Monday it would send more federal troops to the northern state of Coahuila following the massacre of 17 people at a private party there. Gunmen stormed the party in the city of Torreon on Sunday and opened fire without saying a word.
Investigators had no suspects or information on a possible motive but Coahuila is among several northern Mexican states that have seen a spike in drug-related violence as the Gulf cartel and its former enforcers, the Zetas, fight for control of drug-trafficking routes.
The Coahuila state Attorney General's Office said in a statement early Monday that the death toll rose to 18 overnight after one of the wounded died. Later Monday, state Prosecutor Jesus Torres Charles said that person was still in intensive care.
There were 12 male and six female victims; among them were four teenagers, the youngest a 17-year-old boy. At least 17 were wounded.
The attack was ghastly, but no longer unprecedented in a region that is slammed day after day by gruesome slayings that authorities attribute to an increasingly brutal battle between drug gangs feuding over territory.