You will need
- - computer,
- connection to the Internet.
The first thing to do is ask their loved ones, not whether they came by accident to your mail. If you at the last session with the mail service not clicked the exit button, you technically left in your mailbox. Another man who sat down at your computer and went to mail, automatically appears in your mail.
If you are interested in information on a mailbox that is registered on the service mail.ru you can help the social network this resource. Going into "My world" note on the menu item "Guests". It lists the users logged on your personal page in the social network. Perhaps you will see in this list of strangers. Next to the avatar of the user indicates the time at which he visited your page.
You should pay attention to the letters in your mailbox. Review the lists carefully. If any of them were open, but they were not opened by you, it may reveal information about the interests of the person who visited your mail. Often, a targeted letter containing the registration data, payment systems, social networks and any other services.
Modern email services provide users with the ability to use a personal security settings. The main "trump card" of this configuration is defining the IP addresses from which the last time came in the mail. If you use email from mail.ru go to the "Settings" tab and select "Security". In the line "Last login on HTTP you will see the time, date and IP address of last login to the system. In the mail on the website yandex.ru the same thing can be done, if you pass in the items "settings", "Security", "Log visits". To view the IP in the mail gmail.com should turn to "Additional information", which is located in the lower right corner of the tab "settings" under "Latest activity in your account".
Found thus IP address can give information about the country, city and ISP of the place where you visited your mail. You can use this information in a written statement to law enforcement.