Unethical? Yes. But illegal?

Hypothetical; An employee in an IT capacity at a company sends the owner of that company an email and then later wants to change it for whatever reason. The IT employee (with access to the email account) accesses the owners email account and goes in and deletes the email from the inbox (& deleted folder), not realizing that email was already downloaded by the owner on a mobile device. Obviously this is unethical. My question; are there any laws pertaining to this?