Sunfish is correct.
A tipoff and/ or police intel definitely at work here.
The crooks always seem to assume the cops/ customs are idiots and they are waaaay smarter and not going to get caught.
Sometimes they may not, not the first time or maybe the second but eventually the law gets them.
Trying to ship drugs internationally is even more risky than doing it domestically yet they keep trying and usually get caught.
Most smaller criminal organizations, apart from maybe some of the worlds largest drug cartels ( eg Central American cartels) cannot match the resources of the law enforcement agencies.
Corruption and having the ability to buy off agents/agencies and buy their intel, as in Central America is obviously a huge problem.
Unless you are a very clever lone individual who isn't even a blip on anyones radar your chances of getting away with a major crime is going to be very slim.
A trail of some kind is always left behind and the more people who are in on it the bigger/longer it gets, usually at a geometric rate. People are careless and have big mouths so something always gets out.