In applying direct observation to obtain data, few researchers in the field of commercial forensic interviewing (CFI) have to date focused on the design and implementation of direct observation and descriptive analysis. Direct observations are useful for collecting data, due to the sensitive nature of a commercial forensic interview (CFI) involving Commercial Forensic Practitioners (FPs) and interviewees. The aim of this study is twofold: First, develop an observational checklist. Second, to apply it in a CFI to document direct observation of the interactional style of FPs, interactions, and relational dynamics. A descriptive analysis checklist was developed, drawing on interview techniques previously identified as permissible in a South African legal context and developed by applying directed content analysis. Two observers, FPs trained as academic researchers, independently documented their observations in the CFI context. The observers’ responses yielded significant levels of consensus (≥ 80%), and the results demonstrated several relational qualities which successfully identify the FP’s interactional style; the relational dynamics at play during the interview (by observing the actions, impact, and reactions of the participants), and ineffective relational dynamics, which thwarted the goal of eliciting useful information. This study highlights the need for direct observation and contributes to the development of an effective observational checklist unique to the CFI context.