Victor Rodriguez, 57, of Brownsville, was arrested March 29 in the border town of Matamoros by investigators from the Mexican attorney general's office.
Rodriguez has been linked to a botched smuggling operation uncovered May 14 when dozens of illegal immigrants were locked in a tractor-trailer and abandoned in Victoria, 100 miles southwest of Houston.
Seventeen immigrants were found dead in the trailer, and two others later died. The victims, including a 5-year-old Mexican boy, died from dehydration, hyperthermia and suffocation.
Executive Assistant U.S. Attorney Nancy Herrera in Houston said that "until the legal process continues in Mexico, we can't talk about a possible extradition request or any legal options we have."
Officials said most of the immigrants were from Mexico, while others were from El Salvador, Guatemala and Honduras.
Those who survived told immigrant advocates of having crossed the border in various ways - all illegal - and then gathering in Harlingen, Texas, for a 300-mile ride up Highway 77 to Houston.
That was done locked inside the back of a huge trailer truck - crowded, with no light, no water, and very little air.
"They didn't realize the danger of the situation," said Mexico's consul general in Houson, Eduardo Ibarrola, at the time. "They realized (too late) that there were so many people, that there was no air and that they could not get out."