Then, I meet someone familiar with the fugitives.

It took months to arrange, but one insider agreed to explain the inner workings of Boshe's drug operations.

He insisted he wasn't involved in making drugs. However, his relatives, including his ex-wife, his current fiance and her family, were all arrested in that big raid on Boshe.

The meeting came with two conditions. First, I had to agree to hide his face and his name. And second, we had to meet in an eerie, abandoned warehouse in the mountains outside Shenzhen.

Together, we look at photos of Boshe's fugitives.

The man points out the people he recognises, some of the drug bosses and others involved in production and trafficking, but it's clear that he doesn't like this exercise.

He keeps looking over his shoulder, even though we're in an empty room.

He is quite young, in his mid-20s. And even though he insists he's not a drug maker, he looks like he could be training to become one.

A tight white shirt stretches over his sizeable belly and he's chain smoking eye-wateringly strong cigarettes. Eventually, he begins to open up.

 There were three major families who ran the Boshe drug trade.”

“After the drug making technique came in,” he continues, “the first family really worked together on it and the drug profits were really high. One family taught another how to do it.”

For years, the village thrived by producing mountains of meth. The relative's own clan specialises in meth, and he's quick to advertise its wonderful properties, explaining brightly that if you take it “you can play cards for days”.

A rival clan specialises in ketamine, he says.

“Drug making is based on market demand,” he says, conceding that “the demand for ketamine is almost the same as the demand for meth.”

But Boshe's success became a weakness. The chemical labs grew over time, becoming too elaborate to move quickly.

“In the past, when the labs were smaller, it just took one hour to move them,” the relative says.

“But, the more drugs that were made, the bigger they got. It was all too much. So the labs couldn't be moved in an hour anymore.”

“The raid was a big surprise,” he says.

“All the telephones stopped working in the village because the signals had been jammed.

“People nearby tried to warn people in Boshe, but the calls couldn't get through. When the villagers found out, some tried throwing the drugs into the sea.

 They did throw away a lot, but there were too many drugs! They couldn't get rid of them all.”

But ultimately, the raid did little to dent drug operations in and around Boshe.

Lighting yet another cigarette, the man exhales a cloud of smoke before explaining that the region doesn't just make the final versions of the drugs.

Crucially, they also manufacture the precursor chemicals that go into those drugs. Boshe's gangs have mastered entire supply chains.

And that makes drugs even cheaper. Ketamine now costs less than meth, he says.

“Drug prices are still dropping because lots of drugs like meth are becoming easier and easier to make. There are too many people who know how to make drugs, so the prices are really cheap.”

China's leaders are reacting to the problem, launching high-profile crackdowns.

A six-month drug operation that started late last year resulted in 133,000 arrests, and more than 600,000 people were caught taking drugs.

The numbers are almost double those for the same period a year earlier - a dubious victory for police.

It was a violent period, too - nine police were killed and another 657 officers were wounded.

Globally, ketamine seizures are soaring, rising 85% between 2012 and 2013. Much of the world's ketamine is streaming out of China.

Until 2012, 60% of the world's ketamine seizures took place on the narrow border between mainland China and Hong Kong. Experts believe that number is probably even higher now.

With so many police watching Boshe, operations are more secretive now, the insider says. But they haven't stopped.

“In China, more than one place is producing drugs,” he continues, pulling the last cigarette from the pack.

“Boshe is just one of the places with large-scale drug production. In lots of Chinese provinces, there are a lot of places producing this kind of stuff.”