"I avoid the street at night, " he says of the unofficial curfew local residents adhere to in Reynosa.

CNN: STORY HIGHLIGHTS

BMW, Sony and Matsushita have set up maquiladoras in Reynosa and Matamoros.

ECONOMIST: One river, one country

Another U.S. client in the Reynosa area, the consultant says, has become concerned about firefights, limiting its hours of operations and building a safe room.

FORBES: Mexico

Last September's deadly blast at a gas plant near the northern town of Reynosa is thought to have been caused by a build-up of gas.

BBC: Mexico City blast at state oil firm Pemex kills 25

Born into a family of traders in Mexico City, he moved to Reynosa a few years ago to follow his passion and open up his own store.

CNN: STORY HIGHLIGHTS

In Reynosa, the bad guys aren't always so easily recognizable.

CNN: STORY HIGHLIGHTS

Reynosa now has 187 maquiladoras employing 42, 000 workers.

ECONOMIST: One river, one country

In Reynosa, one slip-up can cost a lot.

CNN: STORY HIGHLIGHTS

In Mexico, where 94% of citizens see web access as a fundamental right, Twitter is currently being used in towns like Reynosa where residents share data on the current activities of violent drug cartels.

FORBES: Learning About Internet Freedom from Despots and Drug Dealers

The Zetas, who are estimated to have more than ten thousand fighters, control virtually the entire east coast of Mexico, and have laid claim to several of the busiest cargo crossing points on the U.S. border, including Matamoros, Reynosa, and Nuevo Laredo.

NEWYORKER: The Kingpins

In September of last year, a massive explosion at a Pemex natural-gas plant near the northern border city of Reynosa killed 30 workers and caused critical shortages of the fuel, causing the state-run electricity company Comision Federal de Electricidad to switch to more expensive fuels in order to free up some natural gas for industry.

WSJ: Deadly Blast Hits Mexico Oil Giant