In order to properly analyze call detail records, a considerable amount of information should be gathered in addition to the cell tower locations and the call detail report. In this chapter we look at language for use in requesting this information in the most detailed manner possible. Bear in mind that all of the information you request may not be available because different cellular carrier companies’ retention policies vary. Some carriers begin to purge records as early as 18 months after a call is recorded, while others may keep records for several years. The only way to know is to contact the custodian of records and inquire about the carrier’s individual retention policy.

In any case where you are going to seek this information, even if it is a considerable amount of time after the date of the incident, it may be prudent to issue a preservation order to prevent the loss of any further stored data.

Call detail records in and of themselves provide minimal information. This is because the call detail records are used by the cellular carriers for the purpose of financial transactions such as generating bills to the subscriber and also for the purpose of settling accounts with other carriers.

However, when call detail records are needed for the purpose of evidence, additional information is needed to perform a comprehensive analysis. A standard call detail report will not contain any technical information about the individual cell towers or the health of the system at the time. If you only have a listing of calls made and the location of the various cell towers that were used in the transmission and reception of the calls, a lot can be left to interpretation. While locating a cell phone is not possible from historical records, many claims are made as to the location of a cell phone from these records.

In order for the analysis to be as complete as possible, information about the cell towers must also be gathered:

This information is needed so that the analyst can properly identify and map out the specific coverage area of a tower or tower sector.

The language that is included in the following section attempts to capture information about the configuration and health of the cellular system at the time of the incident. It also attempts to capture the history of any calls made, text messages, and data access for the phones in question.

Simply requesting the call detail records and cell tower locations for a cellular phone number will not compel the carrier to give you information that could be critical to your case. The cell phone system and how it works along with examples of the usage of the evidence you are asking for here is covered in Chapter 33.

This example language includes all of the items that you would want to get when requesting cellular phone records in order for your expert to be able to provide the best analysis possible.

In this chapter we looked at some of the discovery issues relating to cellular evidence. We have also included sample language for obtaining as much information as possible for call detail records and supporting information that may be obtained in the course of discovery.