The present invention provides an electronic data document (EDD) and related system and method for use in a computerized clinical trial verification system. In an exemplary embodiment, the EDD is authenticated by the creator and validated by the receiver, and comprises an image of a source document (SD) that comprises a masked record of at least one interaction between a clinical trial investigator and a patient enrolled in a clinical trial, at least one revealed portion of the SD that includes evidence relevant to at least one question in a clinical trial questionnaire, and at least one annotation connecting the revealed portion to the at least one question. The present invention provides a computerized system and method for allowing a clinical trial investigator to answer questions from a clinical trial questionnaire pertinent to a clinical trial of a medical treatment using encrypted and partially masked electronic documents comprising images of original patient records. The process of creating and viewing the partially masked electronic documents preferably does not create local copies that can be recalled later.