At the isolated ranch in northern Mexico, where the bound and gagged bodies of 72 illegal migrants were found recently, soldiers discovered the killers had a cloned pickup, painted olive green, with markings and plates of the Mexican army.

 driver was wearing a deputy's uniform and swore he was a real law officer. But to the Border Patrol agents manning a checkpoint here, something looked funny about the pickup with Webb County sheriff decals.

So the agents called the dispatcher and found all the sheriff's vehicles were accounted for. When they pulled the driver over, they discovered he was an impostor — with a thousand pounds of marijuana in the cab.

With growing boldness, drug gangs and smuggling organizations on both sides of the border are disguising their couriers and assassins in phony uniforms and vehicles, passing them off as mail handlers and oil-field workers, or even Mexican soldiers and Texas sheriffs.

The traffickers have been caught hauling marijuana along the Texas border in fake versions of a Wal-Mart truck or FedEx van. They've employed sham school buses, dummy dump trucks and bogus ambulances.

Law-enforcement officials call them "cloners," and they are increasingly the vehicles of choice in conflict zones where the lines between the bad guys and the law are blurred by corruption.

"Trust me, whatever you can think of, the smugglers have already thought of, and with the Internet and a decent body shop, it's not too hard to make a clone," said Jose Gonzalez, assistant patrol agent in charge of the Zapata sector of the U.S. Border Patrol.

In Mexico, cartel commandos wearing black masks zoom through checkpoints in pickups boldly marked with forged POLICIA FEDERAL insignia. Gunmen for the paramilitary Zetas set up fake military checkpoints and carry out hits in carbon copies of army trucks.

In one of the boldest incidents, gangsters in a convoy of seven phony police vehicles kidnapped a mayor from his home near Monterrey last month. The mayor's body, blindfolded and hands bound, was found two days later, on a rural road. The alleged assassins were municipal police wearing federal police uniforms.

"Impersonating a law-enforcement asset is ingenious and disturbing. It's the tactic of hiding in plain sight. Cops don't want to stop other cops," said Fred Burton, vice president at the security consultancy Stratfor and a counterterrorism adviser for the Texas Public Safety Department.

Burton said the traffickers were taking a tool out of the spy's kit. "What is going to raise more red flags on the border: A delivery van? Or a shiny SUV with smoked windows and a new set of rims?"

At the isolated ranch in northern Mexico, where the bound and gagged bodies of 72 illegal migrants were found recently, soldiers discovered the killers had a cloned pickup, painted olive green, with markings and plates of the Mexican army.

In Mississippi, police seized nearly 800 pounds of cocaine in 2006 from a van covered with Comcast, Dish Network and other cable-company decals. The smugglers even plastered a toll-free number with a "How's My Driving?" sticker on the van's rear door; the number belonged to an adult chat line.