Recent incidents of scaffolding collapses in the construction industry prompt the need for forensic investigations to help engineers have a better understanding of failures, their causes, and mitigation procedures. This paper presents a case study involving the investigation of a bridge scaffolding collapse; where interdisciplinary expertise of professional divers, underwater investigators, and structural engineers was employed. The study presents the process of forensic investigation; including assessment protocol, accurate data collection, evidence collection under water, and preservation of physical evidence. The gathered information describe the incident, type of collapsed scaffolding, underwater photos of the failed scaffolding, side-scan sonar survey of the accident site, scaffolding orientation under water, visible damage, weather, water visibility and conditions, probable mechanism of events, and summary of the incident. The study also presents the used tools/technologies for the identification, collection, preservation, and/or analysis of forensic evidence. The case study underscores the value of forensic engineering techniques to identify design/construction problems and to elevate the understanding of professionals engaged in forensic engineering.