On January 30, 2010, a commando of at least 20 hit men parked themselves outside a birthday party of high school and college students in Villas de Salvarcar, Ciudad Juarez. Near midnight, the assassins, later identified as hired guns for the Mexican cartel La Linea, broke into a one-story house and opened fire on a gathering of nearly 60 teenagers. Outside, lookouts gunned down a screaming neighbor and several students who had managed to escape. Fourteen young men and women were killed, and 12 more were wounded before the hit men finally fled.

Indirectly, the United States government played a role in the massacre by supplying some of the firearms used by the cartel murderers. Three of the high caliber weapons fired that night in Villas de Salvarcar were linked to a gun tracing operation run by the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF), according to a Mexican army document obtained exclusively by Univision News.

Univision News identified a total of 57 more previously unreported firearms that were bought by straw purchasers monitored by ATF during Operation Fast and Furious, and then recovered in Mexico in sites related to murders, kidnappings, and at least one other massacre…

“When the ATF stopped me, they told me the guns were going to cartels,” Hugh Crumpler, a Vietnam veteran turned arms trafficker, told Univision News. “The ATF knew before I knew and had been following me for a considerable length of time. They could not have followed me for two months like they said they did, and not know the guns were going somewhere, and not want for that to be happening.”