Heroin use has long been associated with crime because its importation and distribution are illegal and because many addicted people turn to theft and prostitution to obtain money to buy the drug. In addition, violent competition between drug dealers has resulted in many murders and the deaths of innocent bystanders. From 1979 through 1990 arrests for heroin manufacture, sale, or possession in the United States held steady, but in the 1990s arrests rose as the drug's popularity began to increase once more.
The heroin trade can be enormously lucrative to those in the upper echelons. For decades the Mafia has been involved in heroin trafficking operations, including the "French Connection" of the 1950s and 1960s and the more recent "Pizza Connection," which used pizza parlors as fronts. Other trafficking groups are more loosely based on ethnic or national ties; for example, groups of Chinese, Thai, Nigerian, or Mexican nationals have operated in different parts of the country. In contrast to those in the higher tiers, many dealers on the street level are addicted or imprisoned frequently, and their financial gains are limited. U.S. laws and law enforcement efforts focus on interrupting the flow of heroin into the country as well as the arrest of distributors and persons who commit crimes to support their habits.