trafficking

The police investigation, ordered by the Paris prosecutor's office, will focus on "potential acts of aggravated human trafficking… with multiple victims," according to correspondence seen by the BBC.

The judicial source said authorities were still investigating whether the man had links to drug trafficking networks.

In September a court in the south of the country jailed a man for life for human trafficking, accusing him of sending people to fight "in foreign countries".

In September, the US government blacklisted Barrio 18 as part of its crackdown on drug trafficking.

Vítor Ananias, head of Portugal's police unit to combat drug trafficking, told a press conference that their different nationalities showed the organisation behind them was not just based in one country.