Purpose The continued prevalence of financial crime and the lack of effective commercial forensic interviewing strategies prompted the development, presented here, of a conceptual framework to explain the relational dynamics conducive to interactions during a commercial forensic interview (CFI). The purpose of this study is to present such a framework which may facilitate the process of obtaining admissible evidence in different forums. Design/methodology/approach A grounded theory approach was adopted to develop a conceptual framework, drawing on the findings of a scoping review, direct observations of interactions involving commercial forensic practitioners (FPs) and interviewees, and data obtained from semi-structured interviews, making use of critical realism as a meta-theoretical framework. Findings Data obtained from the review informed the integrated approach of the conceptual framework, thus combining the structure of the PEACE model and creating an optimal interpersonal context informed by the person-centred approach (PCA). Observational data were used to identify the relational qualities associated with the interpersonal styles (clusters of relational qualities) of FPs in the CFI context, thereby contributing to complex relational dynamics. Interview data were used both to describe effective and ineffective interpersonal styles and how they played out in the CFI with interviewees, yielding information that unfortunately proved not to be admissible in a legal context. The findings of the different phases indicated the need for an integrated conceptual approach, the Ponaletso CFI framework, which draws on the structure of the PEACE model and the PCA, as expressed in the relational qualities of interactional pattern analysis (IPA). The framework consists of the interview stage (before, during and after), the structure (phases) of the PEACE model, the type of questions (open- or closed-ended) according to the PCA, FPs’ interpersonal styles (clusters of relational qualities as explained by IPA) and the observable relational dynamics between FPs and interviewees. When FPs use the Ponaletso CFI framework, there is a greater likelihood of extracting admissible evidence because the interview is guided by a clear structure with a step-by-step questioning approach by FPs, while taking into consideration the relational dynamics to which they contribute. Originality/value The proposed conceptual framework considers relational dynamics and how FPs can navigate towards optimal relational dynamics in CFI contexts. FPs can apply the structure, ask appropriate questions at the relevant phases and observe the relational dynamics playing out in the interpersonal context of the CFI. To the best of the authors’ knowledge, this is the first attempt at creating an integrated interviewing framework for conducting CFIs aligned with the legal context in South Africa. Using the Ponaletso CFI framework may aid FPs in obtaining admissible evidence and facilitate an optimal interpersonal context during commercial forensic investigations while respecting interviewees’ constitutional rights.