What Are LUDs?

Local usage details (LUDs) are logs of ingoing and outgoing calls associated with a specific phone number. Phone companies use this information to generate bills for their customers, and law enforcement agencies may request access to the data as part of an investigation if they think it will be relevant to their work. A court order is necessary to view LUDs, but the standards are less stringent than for warrants to search personal property like homes.

The raw LUDs provide basic information, and the phone company will apply appropriate rates and other details later. Usually, a simplified version of the list is reproduced on the customer's bill, providing information about outgoing toll calls so people can understand the charges. The bill does not include a list of incoming calls unless a customer accepted collect charges on an incoming call. Outgoing calls within a local call area, where no toll applies, may not be listed.

Law enforcement agencies that want to access LUDs will need to approach a judge and explain why the data is necessary or helpful. They can access both landline and cell phone call data as part of an investigation. The phone company must turn over the material, and in some cases, customers may not be notified about the inspection of the phone records, depending on regional laws. Phone data may be useful for tracking transactions, identifying contacts, and other aspects of an investigation.

Phone companies keep LUDs for varying lengths of time. The company usually has an internal policy to keep logs long enough to be able to address customer disputes by turning to the raw data, and the law may require companies to keep this information for a set length of time as well. Some companies move data to an offsite storage facility, archiving it rather than destroying it in case they need it in the future.

Customers with concerns about potential uses of their LUDs can ask the phone company about its privacy policies and get information on regional laws in their area. If the data becomes subject to a court order, sometimes the phone company must notify customers to make them aware, while in other cases this does not occur. Usually, privacy protections are more strict for landlines than cell phones. Privacy laws are often in a state of flux, and it is important to check the most recent information to get an accurate picture of how and when private data is available to law enforcement officers.

As society's dependence on technology has increased, LUDs have become a vital tool used by investigators to solve crimes. Not only do call detail records display outgoing and incoming calls, but they also show what time and where someone is when they make or receive a call and if the user has sent text messages.

A cell phone relies on signals transmitted by towers to complete a call. These towers are dispersed throughout the country, giving users a cell signal almost everywhere. As a person moves from one area to another, their phone reconnects to the closest tower. The service provider records the location of the cell towers that a phone uses, and this data is on the LUDs.

Investigators use this data to determine the possible location of an individual in relation to a crime. For example, if a suspect states they were at work instead of across town when a perpetrator committed a crime, the LUD may be able to show the location of the cell tower closest to the phone at a specific time. While data showing the phone remained connected to the tower near a person’s work doesn’t guarantee the individual was or wasn’t involved, a report showing the person’s cell used a tower closest to the crime may indicate involvement. These reports help investigators narrow their suspect pool and determine if someone has been dishonest about their location.

Location isn’t just used to determine where a person was at the approximate time of a crime. Investigators also use it to establish a pattern for a suspect. While the data only reveals which tower a cell phone uses, that is still helpful in determining the number of times a person may have gone to the same location. If a person visits the same spot every Friday night, they may know of a crime committed in that area on a Friday evening. The historical background helps investigators monitor suspects’ movements in different crimes, such as drug dealers, sexual predators and robbery.

Another way that law enforcement officers solve crimes is by using LUDs to establish relationships between two or more people. Occasionally, a suspect may deny knowing another person who committed a crime to distance themselves from wrongdoing. However, investigators review call histories to determine if any communication via call or text has occurred between these people.

Call detail records may determine the depth of a relationship by displaying the frequency of contact between users. A person who calls multiple times a day probably has a much closer relationship than someone who has called only once or twice a year. When combined with the location information, this data is one way law enforcement can put two people together at a given time. This makes it possible for investigators to learn who accomplices or witnesses could be if they already know one or more people involved in a crime.

Local Usage Details are basic reports compared to other types of information stored on a cell phone. Since this information comes from the service provider, they cannot provide details that remain solely on the physical device. This includes information such as GPS location history, the content of text and SMS messages, photos or app usage. While these details make it easier to solve crimes, an investigator needs a warrant and access to the cell phone to obtain it. If the phone is destroyed or sold, the information provided in the LUDs may be all they have to analyze.

LUDs also cannot give investigators an exact location of a person, only that a specific tower picked up their cell phone at a particular time. If their phone is left in another person’s car, stolen, or purposefully left elsewhere, the LUDs report cannot tell law enforcement where that individual was at that time.

Besides providing investigators information and itemized billing, a cell phone provider also uses LUDs for other reasons. These reports also give vital information about the company’s equipment. Reviewing these records lets them know if a tower routinely drops calls or has a high number of calls that don’t connect. This may indicate a problem with the tower. LUDs also give data about connection speed and the number of calls using a tower at a specific time. If the service provider notices that the call level remains high and slow, it may indicate that an additional tower is needed in that area to alleviate the congestion.