It's a staple on some of the longest-running crime shows on television: Communications between people charged with crimes and their lawyers are protected from government snooping under what's known as attorney-client privilege.
In practice, things don't always work that way, especially when it comes to email messages between incarcerated people in the federal system and their attorneys. That's because within the Federal Bureau of Prisons, inmates are asked to "voluntarily" agree to electronic monitoring in order to use the bureau's email system.
This seems like an extremely discriminatory practice. If your paying a lawyer, it cost much less for them to reply to an email vs, scheduling 1-2 hours for a face to face visit or even a phone call.
The end result are people with more means are better protected. Just another example of how the legal system tilts in favors the wealthy and turns it back on everyone else.