WASHINGTON (AP) _ Customs inspectors peering into the tractor trailer at the Colombia-Solidarity Bridge along the U.S. border saw nothing more threatening than a cargo load of cookies.

But after passing the truck through an X-ray machine the size of a car wash, agents caught a look at the real treat stashed in the truck: more than 5,600 pounds of marijuana.

The $7.8 million bust in February at the bridge near Laredo, Texas, offers just one glimpse of how officials along the border and in local communities are taking advantage of advanced technology to outsmart drug traffickers and criminals.

``We're not out to push the state-of-the-art for its own sake,'' says Ray Mintz, director of the applied technology division of the U.S. Customs Service.

But with such tools as a thermal imaging camera _ no bigger than the average camcorder _ police officers can find out whether someone is growing marijuana at home or is handing someone a baggie containing narcotics.

They can even do it in the dark.

The thermal camera equipment relies on very slight differences in temperature to create an image with light and dark contrasts. The tool is so sensitive it can detect a change of a quarter of a degree. So if a suspect carrying drugs decided to rid himself of the evidence, the drugs _ still warm from being close to his body _ would show up a different shade than the screen background. Greenhouse-like lights needed to produce marijuana inside a home give off excess heat that the camera picks up.

The device has made work less precarious for police officers in Brownsville, Texas, who patrol the border and sometimes face gunfire from smugglers bringing in marijuana at night.

``Usually, they can see us before we see them,'' said Ben Reyna, chief of the Brownsville police. ``Now, we're starting to turn that around.''

The thermal camera is the most requested item in the Office of National Drug Control Policy's technology transfer program. Funded by Congress since 1998, the program gives state and local police, like Reyna's unit, advanced equipment from the federal government. More than 110 of the $13,000 cameras have been provided to law enforcement officials nationwide.

``We know these systems work, and we know the cops needs these tools,'' said Barry McCaffrey, the administration's drug control policy director. He is seeking more money for the program.

Other innovations have focused on the same goal of giving law enforcement a better and faster glimpse of a situation. Wearing a tactical video device mounted on a black-armored vest, officers on a drug interdiction team can run through a home and give teammates sitting in a van outside an exact peek at the inside layout and any possible suspects.

Developed for the U.S. Coast Guard, the 6-pound equipment set features a camera the size of a grapefruit atop the vest's shoulder. A communications system is tucked into a pocket on the back. Color images that can be encrypted are transmitted to PCs at another location.

The U.S. Customs service still relies on its mainstay _ X-rays _ to inspect drugs or other smuggled goods. But these systems use four or more times as much energy as the machines that scan luggage at the airport.

The cargo X-ray machine along the Southwest border can scan a 40-foot truck in minutes. A driver brings his truck onto a moving platform, where the vehicle is dragged between two X-ray systems looking for hidden goods.

The machines _ which cost about $3.5 million each _ can catch fake walls or other compartments stashed with illegal drugs. One tractor passing through the X-ray at the Bridge of the Americas in El Paso was found to have several hundred pounds of cocaine concealed in its front tires.

With seven such systems in place, Customs officials conducted 57,000 examinations in fiscal year 1998, seizing 23,000 pounds of drugs, Mintz said. By August, railroad cars crossing the border at Laredo will pass through a similar system.

A minibuster density meter _ about the size of a chalkboard eraser _ also helps to detect whether drugs might be hidden in surfaces.

Not everyone is impressed by the new advances. Some immigrant rights groups say money and attention devoted to improving technology could be used to boost basic conditions under which migrants are found and deported.

``The border control strategy has been very long on high-tech, but very short on human decency,'' said Claudia Smith, border project director of the California Rural Legal Aid Assistance Foundation. Night-vision goggles and special censors can't make up for the lack of working vehicles and holding areas in which to place migrants, she said. ``Maybe there can be some more balance.''

For their part, federal agencies say they hope their advances will make searches and enforcement activity less intrusive. At Miami International and New York's Kennedy airport, travelers selected for a pat-down can opt instead for a body-imaging machine. The low-radiation imaging looks through clothing, and can reveal drugs fixed to a person's body.

A gadget that looks like an oversized beeper _ and can even be turned to vibrator mode like most pagers _ enables officials to locate radioactive material without even checking individual items. The device sounds whenever radioactive material is in the vicinity.

In some cases, the innovations amount to nothing more than some creative uses for existing technology. A scope used by doctors to probe patients' organs takes on new life in drug enforcement: authorities slip it into vehicles' gas tanks to look for drugs.