Title 18, Section 2703(f) of the U.S. Code, part of the Stored Communications Act (SCA), specifically addresses the requirement for providers to preserve evidence. This statute mandates that upon request from a governmental entity, a service provider must take necessary steps to preserve records and other evidence in its possession for 90 days. This allows the investigating agency time to obtain the proper legal process, such as a warrant or court order, to compel the disclosure of the preserved data. The initial request can be made via telephone, followed by a formal written request.

A. Title 18, Section 1030: This is the Computer Fraud and Abuse Act (CFAA), which criminalizes unauthorized access to computer systems and is not related to the legal process for preserving electronic records.
B. Title 18, Section 2703(d): This section pertains to obtaining a court order (a "D order") to compel the disclosure of specific records, not the initial request to preserve them.
C. Title 18, Section Chapter 90: This chapter of the U.S. Code deals with the protection of trade secrets and is irrelevant to the preservation of user email for an investigation.

1. United States Code, Title 18, Part I, Chapter 121, § 2703. Required disclosure of customer communications or records. Cornell Law School, Legal Information Institute. As stated in subsection (f)(1): "A provider of wire or electronic communication service or a remote computing service, upon the request of a governmental entity, shall take all necessary steps to preserve records and other evidence in its possession pending the issuance of a court order or other process."

Source: https://www.law.cornell.edu/uscode/text/18/2703

2. U.S. Department of Justice. (2009). Searching and Seizing Computers and Obtaining Electronic Evidence in Criminal Investigations (3rd ed.). Computer Crime and Intellectual Property Section (CCIPS), Criminal Division.

Page 123, Section IV.B.1, "18 U.S.C. § 2703(f) Preservation Letters": This section details that "pursuant to 18 U.S.C. § 2703(f), a provider must preserve records and other evidence upon the request of a law enforcement agency" and that this allows investigators to "prevent the destruction of evidence while they seek a search warrant or other legal process."

3. Kerr, O. S. (2013). Computer Crime Law (3rd ed.). George Washington University Law School.

Chapter 6, "Statutory Privacy Protection," Section C, "The Stored Communications Act," discusses the preservation obligation under 2703(f) as a distinct step that precedes obtaining disclosure orders under other subsections like 2703(a), (b), or (d). This university-level casebook clarifies the procedural role of a preservation request.