The explanation of Internet technical protocols focuses on how computers communicate with one another. This requires that every computer on the public Internet have a unique address, just as each telephone requires its own number. The computer address is known as the Internet Protocol (IP) address. Identifying the IP address of the computer that an offender is using moves the investigator one step closer to identifying the offender. Some of the difficulties encountered in attempting to identify the IP address of a computer-knowledgeable offender are discussed. The article also addresses issues involved in investigating crimes whose child victims are not in the same jurisdiction as the computer used by the offender; for example, a Web site that contains child pornography may be reported to a local agency far from the geographic location of the Web site's host. The article discusses issues involved in tracking the location of such a Web site. The article concludes with a discussion of the proper collection and analysis of evidence obtained from computers and various storage devices for digital information.