In August 2017, a Wisconsin woman captured after living under an alias for 16 years was sentenced Tuesday to 14 years in prison for kidnapping an Allen Park woman in 2000. FBI agents mining social media discovered Kimberly Lee Johns last year in Marathon County, Wis., where she was living under the name Kim McGuire. She had escaped a halfway house in 2000 while awaiting trial in federal court in Detroit. During the trial, defense attorneys requested to submit numerous emails (dated between 1999-2000), that they contained personal, intimate, and sexual details of the couple's relationship, and therefore showed a consensual relationship between the parties. The Government challenged their admissibility on the basis of authenticity, hearsay, relevancy, and Fed. R. Evid. 403.

Question: the conviction has been appealed, and you are a Digital Forensic investigator who has been hired by John's attorney to provide a report that can be submitted to the Federal court that details the tools and techniques that can be used to authenticate email messages from the time period. Provide two possible situations; with or without legal subpoena to access data from the email providers. Keep in mind that this is a Federal criminal case, and therefore your report needs to be professionally written and note any legal protocols or cases that might impact this appeal.

Reference: https://www.leagle.com/decision/infdco20170314e33