  In this paper we introduce the Organization, Relationship, and Contact
Analyzer (ORCA) that is designed to aide intelligence analysis for law
enforcement operations against violent street gangs. ORCA is designed to
address several police analytical needs concerning street gangs using new
techniques in social network analysis. Specifically, it can determine "degree
of membership" for individuals who do not admit to membership in a street gang,
quickly identify sets of influential individuals (under the tipping model), and
identify criminal ecosystems by decomposing gangs into sub-groups. We describe
this software and the design decisions considered in building an intelligence
analysis tool created specifically for countering violent street gangs as well
as provide results based on conducting analysis on real-world police data
provided by a major American metropolitan police department who is partnering
with us and currently deploying this system for real-world use.
