"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.
"For work email, assume someone is reading your email as someone or something probably is," said Moorhead. "Most companies have filters that read every email, looking for offending words and images that don't comply with corporate standards."
Jones also noted that for most people sending illicit emails, they are going to be fairly easy to trace.
"You know, they could be texting too," he added. "If I were to cheat, I would be texting instead of emailing. Text message retention policies are usually very short -- just a couple of days with the provider.
"If you're cheating or threatening someone, email isn't the smartest tool to use unless you really know what you're doing," said Jones.
Sharon Gaudin covers the Internet and Web 2.0, emerging technologies, and desktop and laptop chips for Computerworld. Follow Sharon on Twitter at @sgaudin, on Google+ or subscribe to Sharon's RSS feed. Her email address is email@example.com.
Read more about privacy in Computerworld's Privacy Topic Center.