TIJUANA — The caller painted an ominous scene: A convoy of 40 vehicles carrying 70 heavily armed and masked men was prowling the streets of Rosarito Beach on Tuesday evening. The three police officers who arrived were quickly abducted. The next morning, their mutilated bodies turned up in an empty lot.
Their heads were found in the Tijuana River later that day.
The assault is believed to be one of the largest in Baja California, and is the latest in a series of precisely executed paramilitary operations that have beset Mexican cities as drug cartels escalate their battles to control key smuggling routes.
With Mexican authorities relying more heavily on the military to combat drug smuggling, traffickers have responded in kind, forming large forces of assailants and arming them with frightening arrays of weaponry.
In April, nearly two dozen heavily armed men tried to assassinate Baja California's top-ranking public safety official in a shootout on a Mexicali street. The attackers fired grenades and more than 600 rounds from assault weapons, wounding three bodyguards.
Over the last year, commando-style raids have been regular occurrences in Tijuana, with convoys of masked gunmen snatching victims from restaurants and street corners in brazen daylight raids.
"It's a disturbing manifestation of the latest drug war frenzy.... The militarization of the drug war in many ways on the side of law enforcement has corresponded with the militarization of tactics and personnel on the criminal side," said David Shirk, director of the Trans-Border Institute at the University of San Diego.
The situation, Shirk added, "has heightened the competition and raised the stakes in a way that has led to extreme violence, at a level we have not seen before in Mexico."
In Nuevo Laredo, on the Texas border, a raging turf war between the Gulf and Sinaloa cartels has killed more than 230 people in the last 18 months.
The defection of an anti-drug commando unit, the Zetas, from the Mexican military to the Gulf cartel in the late 1990s paved the way for military-style assaults, experts say.
Federal officials say they killed or captured the original group, but they believe jailed Gulf cartel leader Osiel Cardenas still has at least 120 cadres trained by the Zetas at his command as recently as last August, and increasingly is using them to battle the rival cartel led by Joaquin "El Chapo" Guzman.
But the violence is not limited to cities along the U.S.-Mexico border. In Apatzingan, in the central state of Michoacan, four men were killed and a police officer and four bystanders wounded in an Aug. 18 shootout between rival drug gangs that involved dozens of paramilitary gunmen in 10 vehicles.
Two weeks earlier, police in nearby Uruapan, also in Michoacan, had arrested a group of 10 suspected drug gang members armed with AK-47s and AR-15s.
Cartels also are using increasingly brutal methods to intimidate their enemies. The Rosarito Beach beheadings followed the decapitation in April of a police commander in Acapulco, whose head was found in a public plaza.
Jose Luis Santiago Vasconcelos, the top organized crime prosecutor in the Mexican attorney general's office, has taken over the investigation of the Baja California beheadings. In an interview for today's editions of the Mexico City newspaper El Universal, Santiago said the abductions and beheadings were characteristic of the brutal Central American-based Mara Salvatrucha gang, which has become increasingly involved in the Mexican drug trade.
"Acts like the ones we have just seen are manifestations of groups related to the Maras," he said. "We have seen the phenomenon of decapitation in El Salvador, a brutal act of intimidation that is occurring here as drug gangs are worn down and resort to recruiting this kind of group."
Jeffrey McIllwain, a criminal justice professor at San Diego State University who studies border security issues, believes the violence is a sign that pressure from law enforcement is affecting the cartels' bottom line.
"The fact is that it has hurt operations, severely in some cases
In Baja California, the crime wave could signal an escalation of the fierce war to control the lucrative Tijuana smuggling corridor, which traditionally has been controlled by the Arellano-Felix cartel. Several top-ranking members of the cartel have been killed or arrested in recent years, and other cartels may be sensing weakness, experts say.
Some recent attacks were shocking for their audacity, experts say. Last month, three men armed with AK-47s stormed into the Mexican federal attorney general's office in Tijuana and shot two agents, killing one. In December, assailants attacked the Tijuana home of a state police commander, killing two of his bodyguards. In October, Tijuana's chief of homicides narrowly escaped an attack by assailants who fired more than 50 bullets at his car.
"It's a more aggressive form of violence, with new ingredients," said Victor Clark, a border expert and director of Tijuana's Binational Center for Human Rights.
Times staff writer Richard Boudreaux in Mexico City contributed to this report.