A very interesting and sometimes controversial procedure that is part of the narcotics interdiction processes are called "Pass Throughs" or "Follow Outs".
In this day and age of narcotics interdiction, it's not just office work and surveillance's. There are many times at the Border when you get a large narcotics load, usually over 100lbs., in a "specially made compartment". When discovered, Inspectors notify Customs/DEA agents to come down. The agents will try to persuade the driver/"mule" or "coyote" (smuggler) of the "load" vehicle to come to their senses and realize the sins of their ways by co-operating with Customs/DEA authorities. There are many scenarios, but I will review only a few.
One case involved a trunk load of over 300 lbs. of marijuana in wrapped duct tape just sitting in the trunk. The driver was a lone female driver o.t.a., (out of the area)... single key, not her vehicle, no special reason for the trip, little or no "window dressing". (the usual shopping souvenirs, dirty laundry, travel bags, etc... depending on the scenario).
The reasons for her travel don't match up or seem unreasonable and she begins to show little signs of nervousness... often noticeable only in a minute muscle twitch of the lips or eyelids. A really sharp Customs Inspector will notice the carotid artery and how intense the beat is bulging out of a person's neck. Everything is important for that first few seconds of initial contact... something we all get to know through behavioral analysis techniques.
Visual perception is never really taught well and mostly takes years of experience. Customs has the most extensive research and listings of all the "visible signs" of any other published books I have read over the years on these various subjects like "lying" and "how to detect liars". Depending on how well you write your reports, it is a necessary part of building reasonable suspicion or probable cause. With regard to "border searches", however, there is no real suspicion other than the Subject is traveling from a source country like Mexico, Colombia, Peru, etc... and you instinctively feel a closer look at the driver is warranted, or you want a status check for Immigration reasons. You might even have certain, serious, logically articulateable facts that reasonably conclude a more extensive search is demanded. You might even see a "profile" for smuggling or suspect a certain type of vehicle that is "commonly used for smuggling".
Nowadays, any POV, commercial truck, sea container, boat, plane, train, bus, motorcycle, bicycle, surfboard, shoes, bodycarry, etc.... have been used to smuggle. I have seen a lot. There are some things that I wish I hadn't. (i.e. internal body carries and cadavers... they are gruesome but the cartels don't care how they get narcotics across our borders.)
Cartels also play highly on the emotions of the Inspectors. They anticipate some will be "lazy" and will not want to do their jobs as meticulously as trained or expected. Smuggles will try to impress the Inspector with certain types of drivers. Sometimes, it's just how fast the Inspector is "facilitating" his carloads of people. The smuggler just wants to get through the line.
The smuggling organizations know exactly how to hide things because their methods are very well thought out. (Some smugglers lack "professionalism", employing clumsy techniques to temporarily hide contraband and drugs.) They study the Customs Inspector's every move by stationing their surveillance teams in overview locations in, around and above inspection stations at the border. Cartels even have "nicknames" for certain Customs Inspectors, usually coded on how the particular Inspector engages (or fails to properly engage) his work or reacts to border crossers.
I have seen many instances where I have actually seen more than nervousness or none at all on the part of the driver or passenger(s). In these cases the vehicle exhibits telltale signs of suspicion. For example, "roof loads" are indicated when the ceiling is too "thick, denoted by the top of the driver's head rubbing it. But sometimes "head rubs" are not caused by ceilings filled with drugs. Sometimes it's because the floors are loaded... particularly noticeable in cases where you have a short driver, say 5'3" tall, whose head is hitting the headliner. Other means of vehicle inspection are tapping sidepanels. Any difference in the hollowness of an area indicates suspicion. Diligence, competence and experience help an Inspector to develop tried-and-true expertise on the sounds of an "altered vehicle". All of these instances, and more, take certain training and lots of experience.
The art of smuggling techniques is exactly that, an art. To the common police officer or layman citizen, no one will normally spot these many different concealed compartments unless you have been at the border and seen these compartments firsthand.
In most cases the driver is eventually caught, providing excellent opportunities to train our valuable K-9's. Without these precious dogs we would never find a lot of the well concealed compartments containing drugs.
When drivers are caught agents are called in for interrogation and further investigation. In some instances an agent will "turn" the suspect who decides to co-operate. Suspects are then (usually, but not always) photographed, fingerprinted, and processed as a registered confidential informant. (This would only happen for a controlled delivery.)
In the case of an immediate and fresh seizure, and a "co-operative" driver/mule, the agent doesn't go through the above process when it is believed 'bigger guys' higher up the cartel ladder are within reach. You have to start somewhere.
This is for a follow out. The narcotics are usually unloaded unless there is a time element involved. Sometimes the drugs are left in the vehicle except for a sample to verify the narcotics. The packages might be counted to verify the amounts for later need. They may even be marked. It all depends on the load and the time and experience of the follow-up investigative agent involved.
Remember, these drivers are "watched" and are expected to drop off their load at a certain time and place after going through the border. If the load is too difficult to recover or unload, the level of co-operation of the suspect driver has to be evaluated carefully to determine the level of success. Sometimes the agents take a chance.
In one case such a chance was taken. The driver feigned co-operation, giving the agent a believable story. The driver and vehicle were fully identified, marked, photographed, etc., so it could be found anywhere. Other agents are also provided through the agency or alliance group with state and local narcotics officers and agents... depending on manpower, of course. The driver is allowed to go to his car, provided that he is "instructed" on what to do after dropping off the "load car" at the drop site.
On this occasion, and it won't be the last, the suspect driver was allowed to leave the Customs Secondary Inspection area and given a special release from the agents. He was observed and followed, with agents in front and behind him, to the drop off location. In this instance, the driver saw his move... as soon as he got onto the highway he floored his gas pedal and made a U-turn back to the Mexican side of the border. Because there was no special road block preventing his escape into Mexico, the driver made it back to his country with whatever load of narcotics was left in the vehicle.
On a subsequent "follow-out". The narcotics were removed to prevent the load from going back into Mexico. The road to Mexico was blocked by "yours truly" in the Customs Chase Car and this would usually deter the suspect from absconding back to Mexico. The load car was then dropped off with only a small evidentiary amount of narcotics to conclude the transaction and prevent loss of a major load. I think the U.S. Attorney finally got smart too!
Sometimes the driver is allowed to leave the drop off location entirely and the agents are left waiting for the "pick up" suspect. If no one shows, then the car and narcotics are recovered because of a possibility of being "burnt". No suspect, no case. This is termed a "John Doe" seizure. This also happens when "Port Runners" get away. The narcotics are recovered but without a suspect in custody.
On another "follow out" the driver just took off and "lost" the agents. Sounds impossible but not unlikely. Unfortunately, it happens.
A most regretful case occurred when the usual procedures were adhered to by the 'follow out' agents. The description of the truck and all pertinent details of the driver and relative facts were documented. Yet, almost immediately, the agents "lost" the commercial truck along with its verified narcotics "load" at the first traffic light out of the Customs compound. After that, the truck merely mixed in with the many commercial trucks that are crossing daily using the I-905 highway in San Diego. One would think the agents would have 'marked' the truck with infrared paint or use a "transponder' so as not to lose its location among a sea of almost identical vehicles.
Well, so much for hi-tech suggestions and the national budget. Believe me, I have made many such suggestions over the years. Sadly, with the exception of the many Appreciation Certificates I received for them (minus those stolen by certain Customs supervisors) management never incorporated them into real-life, effective investigative procedure.
Like our brother and sister investigators in DEA who suffer from the lack of available and affordable technology that could greatly assist their drug war work, our managers are still in the Dark Ages. As with the rising number of computer/internet crimes dealing with the transport of illegal and dangerous narcotics, far too many 'older-thinking' DOJ officials are decades behind in technological know-how. In a memorable admission before the House Judiciary Committee last year Janet Reno stated that her total knowledge of computers was how to turn it on... if she could find the switch.
Along with incorporating a pre-thinking, improvisational Sixth Sense to reduce the effect of Murphy's Law during an operation, DEA and Customs agents/Inspectors desperately need advance technology. However, we won't be seeing any until we first replace the human 'machines' too ignorant, arrogant or incompetent who stand in the way of our receiving it.