What's material evidence?

This is apropos a Business Recorder news item "Investigation into cases of tax evasion: Retention of seized laptops, documents justified: FTO" carried by it on Sunday. According to it, "the Federal Tax Ombudsman (FTO), Abdur Rauf Chaudhry has ruled that retention of seized documents, laptops, Central Processing Units (CPUs), etc, by officers of Directorate of Intelligence & Investigation (I&I) over a protracted period is justified as these items constitute material evidence for production in a court."
No doubt, the FTO must be praised for making such accurate ruling. Material evidence means proof or testimony that has significant relationship with the facts or issues of a case or inquiry and can affect its conclusion or evidence. It also means that the facts or issues of a case or an inquiry that can affect its conclusion or outcome have a significant relationship with this type of proof or testimony. The material recovered or retrieved from a laptop can, in certain cases, constitutes valuable evidence.