It is difficult to catch someone who has done this because the e-mail company never knows who opened the false account. Pornographers often use this trick. In most cases, forensic tracing of e-mail relies on computer logs. A computer log is a record of each e-mail message that passes through a computer in a network. Unfortunately, this ideal scenario is not typical.
Problems arise when logs are lacking.
Legal limits and international jurisdictional issues can also create tough challenges for investigators tracing e-mail. Smaller ISPs don't turn on the computer logging functions of their computers either because they have inadequately trained staff or because they don't want the responsibility of turning over information about their clients. This can make the investigator's job difficult because there is not enough information to take the next step. Limits of the law. Even when ISPs maintain sufficient records, they vary in their willingness to help investigators.