The multiple functionalities of mobile devices have allowed them to be used for contact-tracing especially with the emergence of an infectious pandemic, for example, in a smart city. This has been experienced, for example, in COVID-19 cases where propagation of infections may not be controlled effectively. Given that data is exchanged between parties it becomes important to have a focus on how this data can be used as a contact trace mechanism. This contract trace mechanism can also provide Potential Digital Evidence (PDE) that can aid to form an objective hypothesis that could be employed during litigation in the event of a suspicious infection, or when a security incident is detected. This paper, therefore, proposes an iterative Concurrent Contact-Tracing (CCT) framework based on digital evidence from mobile devices in heterogeneous environments.