This document discusses several topics related to criminal investigations and digital evidence, including: - Tracing emails through viewing headers and performing reverse lookups - The Comprehensive Drug Testing case established limitations on broad warrants for electronic data. - Data on the scale of government requests received by tech companies like Google, Microsoft and Facebook. - The Stored Communications Act was updated by the CLOUD Act to apply extraterritorially for data storage. - The Carpenter v. U.S. Supreme Court case required warrants for historic cell site location information.