But Nigerians were paying thousands of dollars a week to Mexicans, Colombians and Bolivians to teach them a new form of production that pumps out bigger, purer batches of meth.

Two years ago, Nigerian authorities arrested four Mexicans from Sinaloa, epicenter of one of the world’s biggest drug trafficking cartels and birthplace of the infamous drug lord Joaquin “El Chapo” Guzman.

“When you found labs before you always had Mexicans and Bolivians behind it, but now the Nigerians are on their own — and they do even better,” said Kayode Raji, NDLEA assistant commander in Imo state.

Experts fear that as production increases, meth will find a domestic market like in South Africa, where “tik” — as it is known on the street — has been described as an epidemic and is the most abused drug in the Western Cape province.

But there is no easy way to stop the rise of meth in Nigeria.

“It will become uncontrollable unless decisive measures are taken,” said Nor, warning: “Otherwise what we have in Mexico will be a small thing compared to Nigeria.”