The idea was that if they left unsent emails in a draft folder, which is known as an electronic drop box, they wouldn't leave a trail and would then be more difficult for anyone to find or trace.
The FBI tracked all of this down when they began investigating the harassing emails being sent to Kelley.
Using metadata footprints left by the emails to determine where the emails had been sent from, investigators traced the emails to an account that Broadwell shared with her husband, the Wall Street Journal reported. They used that information to get a warrant to monitor her email accounts.
Then the rest began to fall into place.
"If you're just a normal person sending email, then it's pretty easy to trace," said Keith Jones, a computer forensic investigator and co-owner of Jones Dykstra & Associates. "Every server [an email] hits going to its destination puts a little identifying line in there... It's like a chain of custody, showing who had the email when."
Simply put, emails generally lay out the tracking information - where they originated and what servers they touched along the way.
However, Jones also said with some work it is possible to hide that trail when sending emails.
"It's very easy to not be traced," said Jones, who noted that he's able to use email in about half the digital investigations they do. "If you take a little bit of effort, you can make it look like it came from someplace else... You can fake the originating address by using an anonymizer."
An anonymizer -- also known as an anonymous proxy -- is a tool specifically designed to make online activity, like emails, untraceable. With email, it hides the sender's identifying information by accessing the Internet on the sender's behalf.
Jones explained that it's akin to someone handing him an envelope to deliver. Jones makes the delivery instead of the other person and he puts his own information in the return address space on the envelope.
The issue is that most people, whether they're sending emails about corporate marketing plans, threats or messages to mistresses, don't bother to use an anonymizer. They simply think that no one, other than the intended recipient, will ever see the messages that they're sending.
"Most individuals and businesses don't think twice about sending private or confidential information over email," said Patrick Moorhead, an analyst with Moor Insights & Strategy. "All it takes is one person knowing your PC, phone, or email password and your email could be read by another person."
And when it comes to company email systems, people should think twice when assuming that no one is paying attention.