A Congressional report on the relationship between cellphone carriers and law enforcement agencies shows that the companies are responding to thousands of requests per day from criminal investigators asking for text messages, call records, location data, and other information on customers. The nation's carriers answered 1.3 million requests last year, revealing how cellphone surveillance has now become a routing part of police work. 

The report also concluded the actual number requests is probably much higher (but is under-reported due to bad record-keeping) and the number of customers affected is actually "several times" higher, because a single request can involve multiple callers and numbers. Police can even request a "data dump" for an entire cell tower, asking and getting the names and numbers of anyone who happened to be near a certain location at a certain time of day, even people who aren't suspects.

Requests for information usually require a search warrant, but in certain circumstances police can declare it to be an emergency, expediting the process without court orders. AT&T says they get more than 700 requests every day, with around 230 of them being regarded as emergencies. Several of the companies did say that they frequently reject many of the requests that they deemed unjustified. T-Mobile even claims to have reported two law enforcement agencies to the FBI, because their requests were considered inappropriate. 

The investigation was initiated by Massachusetts Representative Edward Markey who asked for reports from all the major cellphone companies and then shared the results with The New York Times. Markey is also on a bi-partisan Congressional privacy committee.

As cellphone have become ubiquitous, they are now often the first place that police turn to when seeking information about a suspect and the amount of data that they can reveal often goes far beyond what most customers suspect. Gathering that data on behalf of law enforcement is also now a major part of a cell carriers' daily workload. AT&T billed law enforcement agencies more than $8 million for tracking operations last year, though all carriers say they lose money on the effort since those bill often go unpaid.