Updated: 8/9/2008 1:38:58 PM
A San Antonio couple learned about a Mexican gas-purchasing law the hard way.
The new law is designed to stop bootleggers crossing into Mexico from the U.S. for cheaper gas and diesel.
Bobby and Andy McCulley were headed back to Del Rio from Mexico Thursday, when they were stopped by Mexican officials.
The McCulleys said the officers drove their truck to an impound lot, and they were asked to surrender the keys and their drivers licenses.
When they asked why their truck was being held, they got no response from officers.
"We wanted to see a copy of the law and they wouldn't let us see a copy of the law—of course I don't think there is a copy of the law." Bobby Mcculley said. "They said it was a matter of national security."
Two other Americans stopped by authorities opted to leave their vehicles behind in Mexico, but the McCulleys fought the officers.
They were released after a lengthy wait.
The McCulleys credit the U.S. Border Patrol, the Valverde County Sheriff's Office and their friends on both sides of the border for putting pressure on Mexican authorities.