Given the multiple channels offered by social media apps, the analysis of communication data in criminal investigations has become a challenging task. A multivariate graph, gathering information of different types, can be inferred from communication events (calls, group discussions, etc.) and contact information (e.g. phone directory or app "friends"). Astute transformations are however required to properly associate virtual entities used by a single physical person. This paper proposes a visual analytics approach to support this task relying on graph transformations and proper visual encodings.