Since the early 1970s, the scene of international narcotics trade welcomed a new actor who in a short period of time became one of the most successful players in this field: Nigerian drug trafficking cells. Without having control over the production process, these networks specialize in the role of interlopers, regardless of the type of substance trafficked. In 2007, approximately a third of the cocaine produced in South America that reached European consumer markets did so through West African smugglers, from which more than 90% were Nigerians. Almost all the authors who focused on Nigerian drug trafficking networks have stressed that these criminal enterprises are very difficult to investigate. However, very few of them have actually tried to identify and assess these difficulties and even fewer have concentrated on how the police react to these difficulties during their investigations. While the purpose of this research is to offer a contribution to the general understanding of Nigerian drug trafficking networks, its specific focus is on the police investigation of these illegal formations.