>>> Obtained via a Freedom of Information Act request to the Justice Department, this is the email Attorney General Sessions sent to DOJ staff welcoming/introducing new Deputy Attorney General Rod Rosenstein. (Sessions apparently used the trick of sending an email to himself and BCCing all the recipients.)
Incidentally, this email was sent on May 9, 2017, at 10:06 A.M. (presumably that's East Coast time). Trump would fire FBI Director James Comey later that day, using a memo from Rosenstein as cover.
