Bertrand Monnet, a professor in a French business school and an expert in the economics of crime, spent two years filming every stage of the notorious Sinaloa cartel's drug production in Mexico for Le Monde, to uncover the business of fentanyl, the drug that is the leading cause of death among 18-45-year-olds in the United States. His investigation resulted in the three-part video documentary, Narco Business, which begins in the garages of Culiacan, where narcos manufacture the M30 fentanyl tablets, and ends in the skyscrapers of Dubai, where narcos launder the billions they have made from drug trafficking.

On Tuesday, December 5, we asked our readers on Reddit to send Monnet questions about organized crime, the explosion of fentanyl onto the drug scene, and how fentanyl is produced and exported. Read Monnet's answers below.

This conversation has been edited and condensed for clarity.

How did you gain the narcos' trust?

Bertrand Monnet: I've been working on the Sinaloa cartel, and this cartel only, for about 10 years. In the beginning, a lot of narcos refused to meet me. A friend of mine, David Beriain, a famous Spanish journalist who was killed by the Islamic State group in 2021, and who worked on the cartel for years, offered for me to meet a "middle manager" of the cartel. After two years, I gained the trust of this man and he arranged for me to meet the nephew of El Chapo Guzman, the famous cartel drug lord who is now in jail in the US.

This person does not belong to the cartel anymore, but of course, he has kept a strong influence on some of its leaders. And he agreed to help me.

First of all, I cannot wrap my head around the idea that you were there in person risking your life so many times. Recently I have read that, in Spain, cocaine seized contains more than 70% of fentanyl. This is a worrying matter that few media cover.

Thank you. But I did not take any risks because I had time and I have taken that time to make the right contacts to be welcomed on the cartel's territory. So despite the presence of heavy guns in the documentary, the territory of the cartel was, for me, the safest in the world while I was there.

Regarding Spain, I haven't been there for this investigation, but yes, I know that seizures have been made, proving that fentanyl was sent to Europe. It's not surprising that it's mixed with cocaine because the cartels have had suppliers in Europe for years. What do they sell to them? Cocaine. So now they mix cocaine and fentanyl to make the local suppliers "test" the European market.

Is fentanyl difficult to manufacture?

It is absolutely not difficult to manufacture. Unfortunately, right? But what is essential is the ability to import the product, pure fentanyl. Since this medicine is very potent, its export is very controlled. It takes a strong ability to corrupt top executives within official laboratories in China, which is not an easy game.

In order to produce a drug that does not immediately kill thousands of people, it also takes a "know-how" and one has to be taught that. It can take months. At the end of the day, unfortunately, the groups manage to produce "safe products" that kill thousands and thousands of users.

What is the recipe for fentanyl?

I have observed the process of producing fentanyl. But of course, I won't share the recipe here! The authorities know which components have to be tracked and seized, but the flow is still difficult to identify because the cartels manage to corrupt all the steps they have to go through – customs, logistics, and so on.

What do cartels do with all their money? How and where is it laundered?

Cartels launder their money in several ways, but mostly by using tax havens. Once this money has been laundered, they invest it in many businesses... In businesses they can gain control over local political authorities that manage public tenders.

For example, once laundered, they invest millions of dollars into construction companies so that they become eligible for public tenders, for example, to build the new terminal of a local airport or new highways, or legal businesses that are in the hands of the political authorities they have corrupted for decades. It's a magic business for them. They make billions by selling drugs, they launder the money, and then they make billions by getting public tenders adjudicated by politicians they corrupt.

It really just comes down to money doesn't it? They want it and will do anything to get it (and power).

Absolutely, yes. They are fascinated by money. The Mexican criminals have to be considered as business extremists just as terrorists can be considered as ideological extremists. They already kill just to make money. It's money first: They don't aim for power. They need to control power through corruption in order to make money through elicit business. But the Mexican cartels are very different from Columbia's Pablo Escobar, who at the time aimed to become elected senator. Mexican cartels are just after the financial power, not the political one.

Who is the biggest consumer of the product and why?

The US. First of all because it is the closest market for the Mexican cartels. And because, in the US, there was a pre-existing consumption of opioid medicines prescribed by doctors and pushed by laboratories, which has been brutally stopped by the rapid reaction of the state, leaving hundreds of thousands of consumers without any other solution than having to move to heroin and then fentanyl.

Around 95% of fentanyl produced by Mexican cartels is bound for the US and Canada – it's impossible to know the exact balance between the two. In Mexico, consumption is very small. The cartels forbid it. The remaining quantities are consumed in other countries, especially in Europe now, where the narcos are testing the market.

Do you find that the rise in fentanyl use coincides with the "war on drugs"? Since legitimate drugs, prescribed by real doctors, have been made nearly impossible to obtain for those with chronic pain.

The war on drugs is extreme. And therefore the legitimate use of not only fentanyl but all opioids is more and more inaccessible to patients. But it could be fixed by the Biden administration's plan that has been put in place to address the health challenges posed by the fentanyl crisis.

Is there any evidence for a state sponsoring fentanyl production and/or trafficking?

No there is no evidence. The fentanyl used by the cartels to produce the M30 tablets comes from China. I have observed it in one lab myself, but I don't think it is sufficient to designate China as responsible for the trafficking as a state.

It might be sexy to consider that China could sponsor this trafficking because it has raised a major health issue in the US, but there is absolutely no proof of this. What the people I met within the Sinaloa cartel have said is that, at the top management level of the cartel, there are bosses who directly negotiate with Chinese intermediaries who are in contact with some people who produce the component of pure fentanyl.

You often hear about "fentanyl-laced marijuana." Is there any evidence of lacing on purpose?

For marijuana, I don't know. But for other synthetic drugs, you are right. Many people die from fentanyl without being conscious they have consumed fentanyl because it has been mixed with other drugs by dealers.

Will we eventually see the scale of the plague of fentanyl in the US spread to the rest of the world?

I don't know. Except for in Canada, where it's already the case. It might happen in Europe, but the local authorities are very cautious because of the situation in the US. But, in my opinion, this is a possibility in Brazil because there are existing connections between Mexican cartels and Brazilian criminal organizations – and because the use of very strong drugs, like crack, is already more spread within Brazilian society.

How effective have militaristic responses to the issue of fentanyl been, and in the case that you believe that they are ineffective, what tactics could states pursue to attempt to effectively combat organized crime groups both locally, and trasnantionally?

Militaristic approaches are clearly not sufficient to combat organized crime. The strongest efforts have to be deployed on the markets to reduce consumption. And the strongest efforts have to be put into pressuring the banking havens that are essential for the cartels to launder the billions of dollars they earn through their trafficking, including the trafficking of fentanyl. The US and EU are not doing such a thing at the moment.

Is there any end in sight to the fentanyl crisis? It seems like the production and smuggling is unstoppable.

Yes, sure, let's end on an optimistic note. The only way to tackle this trafficking is, once again, not through a militaristic approach, but by pressuring the banking havens to shutdown the opacity of the financial systems. It is clearly possible, the US and the EU have recently proved they have the capabilities to apply the strongest sanctions against a state which is much more powerful than any banking haven in the world – Russia. Why don't they do that against these black holes of the economy? It has to be done, and it doesn't seem too difficult to do. It's just about the political will of the states.