Criminal behaviour is defined by the laws of particular jurisdictions, and there are sometimes vast differences between and even within countries regarding what types of behaviour are prohibited. Conduct that is lawful in one country or

jurisdiction may be criminal in another, and activity that amounts to a trivial infraction in one jurisdiction may

constitute a serious crime elsewhere. Changing times and social attitudes may lead to changes in criminal law, so that behaviour that was once criminal may become lawful. For example, abortion, once prohibited except in the most unusual circumstances, is now lawful in many countries, as is homosexual behaviour in private between consenting adults in most Western countries, though it remains a serious offense in some parts of the world. Once criminal, suicide and attempted suicide have been removed from the scope of criminal law in some jurisdictions. Indeed, in the U.S. state of Oregon the Death with Dignity Act (passed in 1997) allows terminally ill individuals to end their lives through the use of lethal medications prescribed by a physician. Nonetheless, the general trend has been toward increasing the scope of criminal law rather than decreasing it, and it has been more common to find that statutes create new criminal offenses rather than abolishing existing ones. New technologies have given rise to new opportunities for their abuse, which has led to the creation of new legal restrictions. Just as the invention of the motor vehicle led to the development of a whole body of criminal laws designed to regulate its use, so the widening use of computers and especially the Internet has created the need to legislate against a variety of new abuses and frauds—or old frauds committed in new ways.


Africa
Criminal offenses in most modern African countries are defined in criminal or penal codes, a radical departure from the uncodified English criminal law on which many of these codes are based. Because of their origins, these codes generally reflect the penal assumptions of the original colonial power. The main concessions to local African values or problems are the inclusion of legislation against various customary practices, notably witchcraft; the extension of the criminal law in states with planned economies to cover economic crimes against the state; and, as a consequence of the soaring rate of some kinds of crime, special provision for certain offenses (e.g., armed robbery). Special tribunals, not subject to the ordinary rules of procedure, have been established in many African countries to deal with such offenses.
Sierra Leone retained a greater role for traditional, or customary, law than most other African countries. A former British territory that obtained independence in 1961, Sierra Leone adopted a “general law” based on English common law and on the statutes of the national legislature. In the mid-1960s those laws were consolidated in a single statute, but most of the population lived in rural areas and largely were governed by what was called “customary law.” Whereas general law now applies to the entire country, customary law, which originated in the customs and cultures of the indigenous peoples, still varies by area or district. Customary law is enforced in separate courts in which the judges are politically appointed tribal elders.
Nigeria established a tripartite system of criminal law and criminal justice. Its criminal code is based on English common law, but there is also a penal code based on the Sharīʿah and a customary law based on local traditions. In Zambia, local criminal courts handle the more-serious criminal cases, while customary courts handle most civil cases and less-serious criminal cases. Customary courts differ widely throughout the country—there are no lawyers and few formal rules of procedure, and the courts’ decisions often conflict with the formal law. In Uganda, in addition to formal criminal courts, customary courts are authorized to hear civil cases and criminal cases involving children, but in rural areas they often hear the entire range of criminal cases, including murder (homicide) and rape. In Zimbabwe, the Customary Law and Local Courts Act of 1990 created a single court system that hears both civil law and customary law cases at all levels of the judiciary, including that of the Supreme Court.