Six dozen defenseless men, women and teenagers were pushed up against a wall. A squad of professional killers opened fire on them with automatic weapons and then finished each victim off with a point-blank shot to the head.
They dreamed of joining us, here in this country of opportunity. Instead, their corpses, including that of a pregnant woman, were left to bloat in the open air, to be discovered later and photographed in a sickening heap.
For those of us who remember the tragedy of Latin America's recent past, seeing the images of last month's massacre of 72 immigrants in northern Mexico is like reentering an old and very familiar nightmare.
Not long ago, dictators ruled most of Latin America. They had large groups of people kidnapped, tortured and executed in secret. Their crimes against humanity hit nearly every corner of the region, from cosmopolitan Buenos Aires to provincial Guatemala City.
But this new act of mass murder was not the work of a military junta run by generals. It didn't take place in a tiny banana republic without a judicial system worthy of the name.
It happened in the proud, multiparty democracy called Mexico, a country with ample social freedoms, including a vibrant free press. And it wasn't an isolated occurrence. A report last year by Mexico's human rights ombudsman said at least 400 mass kidnappings are reported in Mexico every year, many involving the rape and murder of hostages.
Modern death squads are operating freely in northern Mexico, extorting those who wish to come here, where relatives and jobs await. The kidnappings and murders of immigrants carried out by these groups are a stain on Mexican democracy, and many commentators there recognize this.
"The abuse against migrants is an everyday embarrassment we don't want to talk about because it would rob us of all our moral authority before our neighbors to the north," columnist Alfonso Zarate wrote in response to the massacre in the newspaper El Universal.
"Mexico demands respect for the human rights of 'illegal' workers in the U.S.," Zarate continued, " ... but is now itself under the microscope of the international community, which is rightly scandalized and indignant."
The victims found near San Fernando, Tamaulipas, were killed, according to media reports, after their smugglers-turned-captors demanded more money from the migrants' families. Some were pressured to work as drug couriers but refused.
As with the many killings of police officers and officials in Mexico, the San Fernando massacre was an act of psychological warfare. Such extreme violence is meant to spread fear and thus make it easier for the killers to impose their will on the living.
If we stay silent about their crime, if we treat it as just another episode in Mexico's unwinnable drug wars, then we'll allows the killers to win.
And yet, here in the United States, the expressions of outrage from the immigrant rights movement have been muted. You could say they are a mere whisper compared with the very loud campaign against Arizona's SB 1070, a law whose most controversial provisions will probably never go into effect.
We should see the killings as a blunt reminder of the reasons why people so desperately want to come here. And we should speak of San Fernando with the same horror as we do El Mozote and the Naval Mechanics School of Buenos Aires -- sites of the most heinous crimes committed by the militaries of El Salvador and Argentina in the 1970s and '80s.
It's not just the killers who deserve our moral outrage, it's the failed judicial systems that allow them to thrive without fear of punishment.
In Latin America, the massacre has already provoked much reflection and protest. The government of Honduras, home to the largest number of its victims, announced it would take new steps to try to discourage illegal immigration to the U.S.
In Mexico, the northern city of Saltillo witnessed a rare event just days after the Aug. 23 massacre: a march by 200 undocumented immigrants, carrying the flags of El Salvador, Guatemala and other Central American countries.
"Our countries deny us the opportunity for economic development," the demonstrators said in a written statement, after marching through the city with covered faces. "But Mexico denies us the opportunity to live."
To stop SB 1070, we've seen Angelenos drive across the desert to Phoenix to march, to denounce both the governor of Arizona and the mad sheriff of Maricopa County, Joe Arpaio.
But I've yet to hear of any rallies at the Mexican consulate or anywhere else here in Los Angeles, demanding that the Mexican government prosecute those guilty of so many migrant killings and disappearances.
Most of the country's leading immigrant rights groups haven't even bothered to issue a news release.