Centre for International Crime Prevention (CICP)
CICP is the UN Office responsible for crime prevention, criminal justice and criminal law reform.
Crime Statistics by Country (NationMaster)
Coverage is for a variety of topics including: assault, theft, corruption, counterfeiting, drugs, homicide, gun violence, human trafficking and more.
United Nations Office on Drugs and Crime (UNODC) Data and Analysis
Coverage includes: crime, corruption, drugs, human trafficking, money laundering, transnational organized crime, crime trends and more. A good jump off page is their data page.
Crime in the United States
Annual FBI Crime statistics for the US.
International Narcotics Control Board (INCB) Annual Reports
Global drug situation, analyses of trends in drug abuse and drug trafficking
National Criminal Justice Research Service (NCJRS)
The NCJRS Abstracts database is a great place to search for criminal justice related information covering US and international sources and issues. Some are available as Full-Text.
UN Interregional Crime and Justice Research Institute (UNICRI)
The UNICRI Documentation and Information Centre has a comprehensive collection of data.
UNODC Homicide Statistics
The dataset covers 207 countries and territories and provides data on homicide levels, trends and contextual characteristics.