Four drug traffickers were captured by police in Tehran upon return from abroad. During the operation, 6 kg of cocaine were seized and the cartel’s leader and three other members were arrested, said General Ali Moayedi, anti-narcotics police chief. Saying that South America is the world’s biggest cocaine producer, he added that foreign accomplices of the drug lords are also being identified by the country’s anti-narcotics police force, IRNA reported.