The US embassy employees, accompanied by a captain in the Mexican navy, were traveling on a back road through the southern state of Morelos in a car belonging to the US embassy on the morning of August 24, reported Excelsior. As they made their way toward a navy base in the area, a truck carrying several federal police officers blocked their path and opened fire after the diplomatic vehicle (a Toyota SUV) failed to stop. According to Mexican authorities, after evading the initial assault, the SUV pulled out onto a highway, at which point three other vehicles began to chase the SUV, opening fire as well. Alternative reports held that up to six vehicles participated in the chase.

The occupants of the diplomatic vehicle called for help, and the pursuit ended when soldiers and federal police officers arrived in support. The Toyota sustained significant damage, though the bulletproof glass and added armor helped save the three men. The two Americans were injured in the attack, one having taken a bullet to the leg and the other suffering a wound to his stomach and hand, while the Mexican was unhurt. The Americans were initially transported to a hospital in Cuernavaca, the capital of Morelos, from which they were later transferred to a Mexico City facility. Both remain in stable condition.

None of the attacking police officers were in uniform, Mexican authorities said, nor were they operating official vehicles. The truck carrying the Americans carried diplomatic license plates, but no other indicators of its status.

It is not yet clear which agency the two US officials worked for, nor what their job function was in Mexico. The embassy said that the men were not agents with either the FBI nor the Drug Enforcement Administration (DEA), though did not provide any more information of their function. The magazine Proceso subsequently reported that the men were in fact working for the DEA, and that they were in the region to support the navy’s efforts to hunt down Hector Beltran Leyva, the ranking member of the criminal organization that bears his name. While Proceso’s report is based on anonymous sources, thus making it difficult to verify, the DEA and the Mexican navy have a history of working together to track down Mexican capos, most prominently Hector Beltran Leyva’s older brother Arturo, who was killed in a shootout with military personnel in Cuernavaca in 2009.

Following the attack, Mexican and American officials alike stated publicly that the incident was merely one of mistaken identity. According to this version, the police were in the area searching for suspected drug traffickers. Upon seeing a late-model SUV piloted by three men that failed to stop at their attempted roadblock, they assumed that they had found their suspects.

However, many disputed this theory, and it leaves a number of details unaccounted for. Among them, if the federal officers were carrying out their official responsibilities, why were they out of uniform? Why were they travelling in unmarked cars that do not belong to the federal agency? Why did they open fire on the SUV, if it posed no threat -- the men were unarmed -- and they had not verified their identity? And, finally, if it was merely an accident, why are 12 federal police officers allegedly involved in the incident being held?

The plausible answers to these questions lie in the realm of incompetence or corruption. For their part,anonymous Mexican Navy officials told reporters that the police officers had intentionally targeted the Toyota, knowing full well who was inside. Regardless of the veracity of the official version, the shooting deepened the rancor between the Department of Public Security (SSP for its initials in Spanish), the agency that houses the federal police, and the navy. This threatens to provoke, a “monumental” and potentially “dangerous” split between the two, according to El Universal.

The incident also furthers a recent pattern of embarrassing incidents for the federal police. Until last week, the most notorious such event was a July shootout between different groups of federal police in Mexico City’s airport and the subsequent firing of all of the more than 300 officers working there. Such scandals demonstrate that the federal police, long touted as a major part of Mexico’s approach to organized crime and insecurity, remains a weak link in Mexico’s institutional structure (though certainly not the only one).

According to many analysts, the heavier reliance on the military in recent years is a mere stopgap, with a revamped and newly competent federal police the eventual replacement for the armed forces that are today operating in a domestic capacity. Throughout his presidency, Calderon has also embraced this logic, even as he deployed tens of thousands of soldiers to all corners of Mexico. By expanding the size of the agency, giving it a larger budget, and making the SSP’s boss Genaro Garcia Luna one of his most trusted advisors, the president has bet Mexico’s future security on an expanded role for the federal police.

Yet as Calderon reaches the end  his six-year term in office, the federal police seems far from being a reliable nationwide replacement for the armed forces. Consequently, the deployments of the soldiers and marines are to continue indefinitely even after Calderon exits his post on December 1. The day when the armed forces can focus exclusively on foreign threats remains well beyond the horizon.