A computer investigation system and method that conducts electronic discovery of desired files across a live network in a forensically sound manner. The investigation entails an examining machine electronically identifying, collecting, and preserving evidence from target machines that is responsive to a set of investigation criteria. The set of investigation criteria is associated with an investigation subject that is identified by a global unique identifier (GUID). As the investigation subject is applied to the various files, the responsive files are stamped with the GUID and preserved in a container file referred to as a logical evidence file (LEF). The GUID allows the results of an investigation to be easily and reliably traced to the particular investigation subject that was applied.