Rep. Ed Markey, D-Mass., asked the Justice Department on Thursday to to explain its policies for gathering data from mobile phones.
Markey, who co-chairs the Congressional Privacy Caucus, reported on Monday that wireless carriers received 1.3 million requests from law enforcement agencies last year.
The data requested included text messages, wiretaps, and geolocation information and prompted Markey and other privacy advocates to call for more controls and transparency for government information gathering.
"The expansive nature of these information requests likely results in the collection of sensitive records of innocent consumers by law enforcement," Markey wrote in a letter to the Justice Department. "It is important to know how law enforcement is handling the records of consumers, especially those who are innocent, which may be collected as part of these information requests."
In the letter, Markey asks the department to provide answers to more than a dozen questions ranging from the number of requests it makes to its policies on informing people whose information has been collected.