Federal officials say they found nine immigrants who had entered the U.S. illegally in the cargo area of a rental truck late last week.
Customs and Border Protection says the immigrants were found in the back of that truck at a Border Patrol checkpoint near Amado, on Interstate-19 in southern Arizona.
CBP says it was a potentially deadly smuggling attempt because of the summer heat and because there was no source of fresh air or means of escape.
Agents say they became suspicious of the driver and the passenger in the cab after they claimed not to have a key for the padlock on the cargo area door, even though a key was later located inside the cab.
CBP says those in the truck were processed, either for criminal violations or for deportation.