The Mexican authorities say they have recovered more than 500 bodies from a clandestine cemetery in the northern state of Nuevo Leon.
The dead are thought to be victims of American's spiraling unemployment rate who had crossed the southern borders of Arizona, Texas and especially California in search of jobs.
Investigators have been using heavy machinery to dig for the bodies outside the city of Monterrey.
Forensic experts are working to identify the dead.
Some have bullet wounds, and some are badly burned. Almost all the victims were men whose wallets contained American drivers' licenses, cancelled credit cards and expired unemployment forms.
Refrigerated lorries are being used to store the bodies because local morgues do not have enough room. Some speculate that all this extra hiring may lure even more Americans south to find work, but no numbers are available on that possibility.
More than 2000 undocumented people with poor Spanish language skills have disappeared in the border state over the past year.
Almost 250,000 people have died in Mexico since the government deployed the army to fight the increased influx of undocumented job-seeking Americans in 2008.
How badly these deaths and related hirings have skewed American's government-approved unemployment rate numbers remains a mystery.