By nature, the dark web anonymizes web activity and prevents tracking of users. Any criminal investigations which involve evidence on the dark web are therefore severely limited. Findings from a workshop held between the RAND Corporation and the Police Executive Research Forum (PERF) on the needs of law enforcement are presented in this RAND Report. Participants included federal, state, and local law enforcement as well as cybercrime researchers, and collectively they identified lack of understanding about dark web crime as a key issue. Other challenges include conducting investigations, legal ambiguity, technical understandings, and tension between civil rights and surveillance. Therefore, increased information sharing and improved training is predicted to have the greatest impact. Due to the global nature of the dark web, effective multi-jurisdictional collaboration presents a significant challenge to criminal investigators. Information sharing not just within the United States but also across international borders is necessary for investigations to function. Increased training on how to collect, handle, and process digital evidence was suggested to bridge the gap between traditional protocol and cybercrime investigations. Ideally, standards across organizations would be developed for collecting digital evidence during investigations. As cybercrime continues to evolve and grow, law enforcement must also adapt.