*2.1. Participants*

This research study was approved by the Willamette University Institutional Review Board. Service providers from law enforcement agencies and legal representatives were invited to participate in this research study. Using snowball sampling, participants were recruited from various cities in Washington, Oregon, and California. Agencies dealing with CSAM were contacted by a member of the research team and asked to participate in this research study. In total, 65 participants from 21 different agencies and/or organizations participated in semi-structured qualitative interviews or focus groups. The majority of participants were from local, state and federal law enforcement agencies as well as various district attorneys' offices. While we had a total of 65 participants, data used for this analysis were from interviews and focus groups with 50 participants, from 16 agencies and/or organizations. This included 33 participants from law enforcement, 11 participants from the legal profession, and six from community organizations. The exclusion of the remaining 15 participants from 6 agencies/organizations were due to technical difficulties in a few instances. In the other instances, participants asked for their interviews to be off the record, and as such, were not recorded or used in data analysis. While these interviews and focus groups were not utilized in data analysis, many participants who asked to remain anonymous work in federal positions and have invaluable knowledge of CSAM and the legal system. These individuals provided context and information to support the research team in focusing the interview questions and in understanding the background of the issue of CSAM in the United States, and in particular in Washington, Oregon, and California.
