Human and drug-smuggling organizations in Mexico are getting their guns from the same places law-abiding U.S. citizens are getting theirs: licensed gun dealers and gun shows, according to court documents.

"There's an iron river of guns flowing to Mexico," said special agent Thomas Mangan, spokesman for the Phoenix office of the U.S. Bureau of Alcohol Tobacco, Firearms and Explosives.

Search warrant affidavits show smugglers are getting guns from "straw purchasers," people with clean records who buy guns for smugglers, who then sneak them across the border for a few hundred dollars.

Records show the weaponry is bought from legitimate dealers in U.S. cities from Tucson to Scottsdale and Apache Junction to Avondale.

On Jan. 21, agents with the U.S. Bureau of Immigration and Customs Enforcement arrested Cedric Lloyd Manuel and Miguel Apodaca of Phoenix with nine assault rifles at the Arizona-Mexico border.

The guns had been bought the day before at gun stores in Apache Junction, Scottsdale and Phoenix. They were purchased by three brothers, Lucio, Rosendo and Marcos Aguilar.

Between November and the Jan. 21 arrests at the border, the Aguilars and others in the straw-purchasing crew bought 66 assault rifles, records show.

"Manuel (Aguilar) stated that he had taken probably about 20 loads of firearms into Mexico over the past couple of months," ATF special agent Heidi Peterson wrote in the affidavit.

The Aguilar family, Manuel Apodaca and the alleged ringleader, Blas Bustamante, have been charged in U.S. District Court with gun violations.

Mangan said the value of guns triples across the border.

He said Mexican crime organizations use the same infrastructure for smuggling humans and drugs north as they do to move the guns south.

He said the agency is working on a number of Arizona gun trafficking investigations while they also work with Mexican authorities to trace guns used in crimes across the border.

One such crime was the shooting of Ramon Tacho Verdugo, the 49-year-old police chief of Agua Prieta, Sonora, who was gunned down as he left the police station Feb. 26.