The objective of this thesis is to design and implement an application, which will on the basis of outputs from selected forensic tools analyse and search for relations among individual participants in communication. The paper will first describe procedures of digital forensics and selected programs used for digital forensics. Following chapters will be dedicated to description of the whole development cycle of the application. The main outcome of the thesis will be a finished application meeting the requirements of the assignment and enabling not only search for relations based on outputs from forensic tools, but also search for additional possible relations from open sources.