EL PASO, Texas (Reuters) - School teacher Ana Isela Martinez was rolling up to the U.S.-Mexico border in Ciudad Juarez to cross for work at an El Paso school in late May when Mexican soldiers stopped her car.
A trusted commuter cleared to use an express crossing lane to the United States, she popped the trunk of her Ford Focus. Troops found two duffel bags, packed with 105 pounds of marijuana.
She insisted on her innocence, but was arrested and jailed in Mexico, where her case shed light on a sophisticated cartel scam that has sent a shudder through thousands of law abiding commuters heading to work each day in Texas.
Accused cartel operatives working on both sides of the Rio Grande had Martinez, known as "Miss Ana" to fourth graders at La Fe Preparatory school where she taught, under surveillance for a year, court documents show.
They noted her regularly timed drive to work using a lane for vetted commuters that is generally swifter and subject to less scrutiny than snarled up traffic lanes used by other border crossers.
Then they had duplicate copies of her car keys made, and slipped drugs into the vehicle's trunk in Ciudad Juarez, which they intended to retrieve after she reached the school in El Paso.
An FBI investigation revealed Martinez was just one of at least half a dozen commuters known to have been ensnared in the scam including a doctor, a hospital worker and students who crossed regularly to the sprawling Texas border city to work or study.
"It is very, very unique," said Michael Martinez, a special agent with the FBI's El Paso field office, noting the sheer range of conspirators involved to pull off the scam, which likely involved other commuters.
"Given what we learned through this investigation, there may be ... several other unwitting transporters" involved, he added.
Details of the ruse emerged this month after the FBI in El Paso arrested accused trafficker Jesus Chavez, who had been under surveillance. A co-defendant, Michael Gomez, escaped after a high-speed car chase and remains at large.
The criminal complaint alleged that Chavez and Gomez, both ex-cons who served time together on federal drug charges, paid lookouts, typically teenagers, to spot commuters waiting to cross to El Paso.
SURVEILLANCE AND COPIED KEYS
Their targets were drivers using the SENTRI lane -- short for Secure Electronic Network for Travelers Rapid Inspection -- an express route set aside for vetted commuters who pass U.S. criminal and immigration background checks and pay a fee for a special crossing card.
The spotters then tracked the targeted vehicles' movements on both sides of the border using GPS devices, and passed on the vehicles' identification numbers to Chavez and Gomez.
A licensed locksmith in El Paso then cut duplicate keys for the vehicles, using key cut codes provided by several other companies.
Working at night, the Juarez-based co-conspirators typically slipped 105-120 pounds of pot into the trunks, placed in two duffel bags each secured with white plastic zip-ties to prevent tampering. Chavez and Gomez are alleged to have retrieved the bags in El Paso.
As well as Ana Martinez, arrested on May 26, U.S. Customs inspectors and Mexican authorities nabbed six other commuters including University of Texas at El Paso student Ricardo Magallanes, who was stopped in November with marijuana-stuffed duffel bags secured with signature zip-ties in his trunk.
Then in December, sports medicine specialist Dr. Justus Lawrence Opot and Marisol Perez, the hospital worker he car-pooled with, were arrested in Juarez after telling Mexican federal police they had discovered marijuana stashed in the trunk of the Mitsubishi car Perez was driving.
After spending six weeks in a Mexican jail, Martinez was released and is seeking to regain her immigration status lost when she was arrested. Her family declined requests for an interview for this story.
Her ordeal, and that of other commuters who despite protesting their innocence have variously been convicted on smuggling charges, spent time in jail and lost their SENTRI privileges, has made other drivers wary. Many now check their trunks before they cross to Texas, and some go even further.
"I bought a $3 mirror ... put an extension on it to check everything ... the four doors, trunk, tires and suspension," said one 45-year-old building contractor as he lined up in the SENTRI lane to cross this week.
"It's turned me into an inspector."
(Additional reporting by Julian Cardona in Ciudad Juarez; Writing by Tim Gaynor; Editing by Cynthia Johnston)