1. Introduction

A person killing another is one of the most serious of all social interactions. The interest in killings has been a major focus of many disciplines, including law, politics, entertainment, criminal justice, criminology, and public health. The passionate and often controversial discourse on this topic often strays from objective scientific evidence to realms of firmly held beliefs and myths. To better understand such a misidentified yet important topic, it is best to start with a review of the data sources that provide a starting point for rigorous scientific discussion. This work will focus on describing American data sources. International data sources are discussed as well, but not those of individual other countries, only worldwide ones. Data sources that collect for non-national areas within the United States (such specific cities) are not covered.