In our last post, we painted a grim picture. Imagine you're driving to work and get pulled over. You're confused about the officer's reason for stopping you since you haven't done anything wrong. However, when the officer searches your car, he finds 50 pounds of marijuana. Although you know nothing about the drugs or how they got in the trunk of your car, you are arrested, convicted and imprisoned on drug charges.

You maintain your innocence throughout the trial, and your attorney files an appeal as soon as you're convicted. Even so, you are sent to prison. After you've been there for some time, the judge who convicted you dismisses the charges against you and your record is cleared.

But what happened? Why did the judge change his mind?

After convicting several other people with cases unnervingly similar to yours, the judge questions whether there may be a connection in the cases. He contacts the FBI, and a full-scale investigation is launched.

It doesn't take long for the investigation to reveal what you already knew. You were wrongly accused and convicted. Moreover, not only did a Mexican drug cartel set you up, but they did the same thing to several other people.

People who routinely drive between Mexico and Texas can apply for a SENTRI pass, which allows them to pass the border patrols with minimal inspection. In order to qualify for a SENTRI pass, people must complete rigorous interviews and have clean backgrounds. Unfortunately, after doing that, they become targets for the drug cartel.

During the investigation, the FBI learned that the drug cartel hired people to monitor the SENTRI lane. They watched for students and professionals who drove through at about the same time every day, and they recorded the make, model and color of their cars.

Then, someone would follow the car into Mexico, wait until nighttime, record it's VIN and attach a GPS tracking device to the car. The VIN was reported to a locksmith, and two copies of the car's keys were made. One copy was given to individuals in Mexico, and they dropped drugs in the person's trunk. The second set of keys was given to members of the drug cartel who are in Texas, and they retrieved the drugs once they were transported into the United States.

The plan was simple and effective, though it caught the eye of a judge for precisely that reason. Several people who were convicted all had unusual similarities in their cases. They were each found with 50 pounds of marijuana in two black duffle bags; the duffle bags were attached to each with slip ties; the drugs were found in the trunk of the car; each of the drivers were in Fords; and they all claimed to have no knowledge of the drugs.

Although the people who were wrongly accused have been freed, their lives will not return to normal unchanged. The judge cannot give them back the time they were imprisoned, and it will be difficult for them to shake the knowledge that their privacy was invaded and they were followed without their knowledge.

Source: CNN, "'Blind mules' unknowingly ferry drugs across the U.S.-Mexico border," Emily Smith, Jan. 24, 2012