The coordinated effort was necessary, because Jamaican organized crime groups, known as posses, are very mobile, well-organized, and adept at using false documents and identities. ATF first became involved in Jamaican organized crime in 1984 at the request of Interpol. ATF efforts uncovered the existence of posses, which may number as many as 30, involved in firearms and narcotics trafficking, as well as money laundering, fraud, kidnapping, and robbery. The majority of posse members are convicted felons or illegal aliens; most have ties with New York and Miami. While initially posses were involved in marijuana importation, distribution, and sale, they have shifted to cocaine in recent years. ATF investigations, based on the knowledge that posses are a national problem, have been successful in the tracing and recovery of illegal firearms and narcotics-related arrests.