  The modern digital world is highly heterogeneous, encompassing a wide variety
of communications, devices, and services. This interconnectedness generates,
synchronises, stores, and presents digital information in multidimensional,
complex formats, often fragmented across multiple sources. When linked to
misuse, this digital information becomes vital digital evidence. Integrating
and harmonising these diverse formats into a unified system is crucial for
comprehensively understanding evidence and its relationships. However, existing
approaches to date have faced challenges limiting investigators' ability to
query heterogeneous evidence across large datasets. This paper presents a novel
approach in the form of a modern unified data graph. The proposed approach aims
to seamlessly integrate, harmonise, and unify evidence data, enabling
cross-platform interoperability, efficient data queries, and improved digital
investigation performance. To demonstrate its efficacy, a case study is
conducted, highlighting the benefits of the proposed approach and showcasing
its effectiveness in enabling the interoperability required for advanced
analytics in digital investigations.
