We believe the science of Intelligence and Security Informatics (ISI) can help with nuclear forensics and attribution. ISI research can help advance the intelligence collection, analytical techniques and instrumentation used in determining the origin, capability, intent, and transit route of nuclear materials by selected hostile countries and (terrorist) groups. We propose a research framework that aims to investigate the Capability, Accessibility, and Intent of critical high-risk countries, institutions, researchers, and extremist or terrorist groups. We propose to develop a knowledge base of the Nuclear Web that will collect, analyze, and pinpoint significant actors in the high-risk international nuclear physics and weapon community. We also identify potential extremist or terrorist groups from our Dark Web testbed who might pose WMD threats to the US and the international community. Selected knowledge mapping and focused web crawling techniques and findings from a preliminary study are presented in this paper.