This case concerns whether a warrant is required to search the information stored on a cell phone when the device itself may be properly deemed “abandoned.”

In this amicus brief, the ACLU and its coalition partners urged robust application of the legal standard governing the admissibility of expert testimony and technical evidence, especially in cases involving opaque or proprietary algorithms.

The information generated by today’s digital devices and online services reveals private matters far beyond what one could learn from physical analogs. In a series of legal filings and a white paper, available below, the ACLU has argued that to keep apace with technological developments and adequately protect our privacy, the Fourth Amendment's warrant requirement must be interpreted robustly. Seizures and searches of digital data must be cabined to probable cause, limited to specific categories of information relevant to the investigation, and closely overseen by a neutral magistrate.