SAN DIEGO - A 41-year-old man who was arrested after border officials found two dying Mexican men in the trunk of his car at the U.S.-Mexican border wept in court on Wednesday as he was arraigned on a federal smuggling charge.

Nicholas George Zakov appeared distraught as his court-appointed attorney entered a plea of innocent on his behalf during a brief hearing in U.S. District Court in San Diego.

Following the hearing, Assistant U.S. Attorney Michael Wheat said that the two men found last week in the trunk of the orange 2012 Dodge Challenger, identified as Tarcisio Casas-Blanco and Jose Quiroz-Casas, were from the Mexican state of Guanajuato.

They had been caught in the United States illegally before and were voluntarily returned - a process where they waived hearings that might have led to formal deportation and instead were immediately returned to Mexico.

When Zakov arrived at the border inspection station after waiting in a line of cars for over an hour, he said he had nothing to declare.

Zakov, who is from North Dakota but now lives in the Los Angeles area, told federal investigators that he was supposed to be paid $3,500 for smuggling the men into the United States, according to the criminal complaint against him. Upon opening the trunk, the customs agents found the two men unconscious. Both men were later pronounced dead at a local hospital.