Abstract The objective of witness investigative interviews is to collect reliable and relevant information. This review aims to document what constitutes relevant information, as well as the techniques that researchers have built or still need to build to reliably collect this information. Researchers and practitioners agree on the ‘investigation-relevant information’ to be collected, which represents around 80% of the content of the investigative interviews (i.e. actions, persons, objects, contextual details, sounds/conversations, and gist information). Many techniques have been developed by researchers to reliably collect most of them. Another content of the interview has largely been neglected in research studies: information pertaining to the interviewee, which represents around 20% of the content of the interviews. We identified six sub-categories: witness characteristics, meta-cognition, viewing conditions, witness’ role, witness’ state, and general knowledge. Several existing techniques could be useful to reliably collect this information but more research is needed. Implications for improving interviewing guidance will be discussed.