Although it’s very difficult to prove that you’ve been snooped on the Internet -- and usually not legal to investigate on your own -- some online services such as Gmail offer tools to show you details about where traffic to your email account comes from, which may provide evidence of snooping. To access this feature, log in to your inbox and click the Details link at the bottom.
If you suspect you’re being snooped, make a report to network support personnel and local police, who can tell you what your legal rights and obligations are. Some tips for keeping your information safer are to avoid creating or using accounts on websites that don’t require a password to log in. Also, avoid open Wi-Fi networks – which don’t require a log in and can be snooped – when you can. Most important, resist the temptation to reverse snoop, which is illegal.
According to “How to Find Out if Someone Has Been Snooping in Your Gmail,” using tools provided by your email and Internet providers can help you legally monitor activity on some of your Internet accounts. For instance, to increase security on all your Google accounts, you can now choose two-factor authentication, which requires you to use more than one method to log in. Remember that even though many software companies offer tools that are legal to use to monitor activity on your computer and smart devices, you often aren't allowed to install them on public and business computers.