"Reasonable" Grand Jury Subpoenas: Asking for Information in the Age of Big Data
Gruenspecht, Joshua, Harvard Journal of Law & Technology
TABLE OF CONTENTS I. INTRODUCTION II. CONSTITUTIONAL AND STATUTORY BOUNDS ON THE GRAND JURY SUBPOENA III. WHY "BIG DATA" IN LOCAL AND THIRD-PARTY STORAGE CHALLENGES THE REASONABLENESS STANDARD IV. THE CASE LAW ON REQUESTING ACCESS TO DIGITALLY STORED DATA BY SUBPOENA V. POSSIBLE WAYS TO BALANCE JUDICIAL OVERSIGHT AND LAW ENFORCEMENT NEEDS A. Restrict or Eliminate the Plain View Doctrine in Digital Search Cases B. Look for Lessons from the Civil Law C. Employ Independent Examiners to Filter Out Irrelevant Material Before Production D. Use Technological Classifications to Narrow Data Production VI. CONCLUSION
Grand juries use the subpoena duces tecum to request and collect evidence held by a party or witness. In so doing, they serve as an investigative arm of the prosecution. (1) Though subpoenas, unlike warrants, can be issued with less than probable cause, (2) they receive less attention from commentators because subpoenas do not result in the state's exercise of its powers to search a suspect's property without his consent. Instead, they are used to request documents and information that the prosecution suspects will be material in the case. The advent of mass digital storage, however, has significantly increased the chances that records of any given document exist and is increasingly unifying the locations in which those records can be found. Both in the case of digital data stores held by users themselves and in the case of data stored by users with third parties, the extent of the subpoena power increasingly rests on the question of how specific a prosecutorial request for documents must be.
Faced with increasing amounts of stored digital information, courts and commentators have attempted to apply old rules in a new context. The knotty Fourth Amendment questions that arise from the production of electronically stored information through warrants have received particular scrutiny. (3) Civil liberties groups have argued that the Constitution demands a probable cause standard for various kinds of digital searches by law enforcement, (4) while public interest and industry coalitions have pushed for legislation to address the issue. (5) While standards for the use of warrants for the collection of evidence have been the subject of judicial conflict, scholarly debate, and public outcry, standards for the use of the grand jury subpoena have slipped by relatively unnoticed. Given the potential scope of digital subpoenas, this is surprising. As one commentator has noted, "[w]hereas the subpoena power is fairly narrow in traditional cases, in computer crime cases it is incredibly broad." (6)
The inexpensiveness of digital storage, the increasing ubiquity of computing, and the growth of the type and number of digital sensors associated with devices of all shapes and sizes means that more data is retained in more hands than ever before. In a world of physical documents, use of the subpoena power was cabined by the investigator's reasonable suspicion of the existence of a given document or communication. (7) An overbroad request from the prosecution to subpoena an entire file cabinet might trigger special judicial scrutiny on a category-by-category basis of the relevance of each category of file therein before production. (8) Now, however, innumerable communications records are created, and few are deleted. often, neither the document creator nor the prosecution knows precisely what records might exist: because of the networking of digital storage, third parties are now significantly more likely to possess digital data, such as personal communications and stored documents, created by others. Today's digital "file cabinets" are significantly larger and easier to locate than their physical equivalents. The privacy problem presented is clear: "searching [electronic storage] in a comprehensive way can expose both crimes and embarrassing private information that can be admissible in court under the plain view exception. …