Wireless Carriers Who Aid Police Surveillance Are Asked for Data WASHINGTON - A leading House Democrat is demanding information from the country's biggest cellphone companies about their role in helping local police departments conduct surveillance and tracking of suspects and others in criminal investigations. Representative Edward J. Markey of Massachusetts, the co-chairman of the Congressional Bipartisan Privacy Caucus, said in a letter sent Wednesday to eight major wireless carriers that he was "deeply concerned" that routine tracking of cellphone use by law enforcement officials in many departments "may violate the privacy rights of Americans." In his letter, Mr. Markey sought data from the cellphone carriers on the number of requests for help they have received from law enforcement officials in cell tracking and surveillance operations, their policies on whether they require the authorities to secure court warrants, the use of cellphone surveillance in nonemergencies, the fees they charge the police and other information. His letter was prompted by an April 1 article in The New York Times on the routine use of cellphone surveillance by local police departments, even in nonemergency situations. Mr. Markey's office provided a copy of his letter to The Times. The move by Mr. Markey puts the cellphone companies in the middle of a protracted public debate over the balance between civil liberties safeguards and the authorities" use of surveillance technology. The issue has received renewed public attention recently as a result of a Supreme Court ruling in January finding that police use of a GPS device on a drug suspect's car without a warrant violated his Fourth Amendment rights. CTIA, the wireless industry trade association, said it had no comment on the Congressional request. Ed McFadden, a spokesman for Verizon, one of the companies from which Mr. Markey is seeking information, said in a statement: "We will review the letter and be responsive. In responding to law enforcement requests, Verizon Wireless follows the law. An AT&T spokesman, Michael Balmoris, said, "We received the congressman's letter and will respond accordingly." Representative Joe L. Barton, the Texas Republican who is co-chairman of the House privacy caucus with Mr. Markey, did not respond to requests for comment. The privacy caucus has no formal subpoena power to gather records. But an official with the caucus who spoke on condition of anonymity in discussing internal matters said that private companies had normally complied with requests from the caucus and that Mr. Markey was confident that the cell companies would give him the information he was seeking. Politicians and lawyers on both sides of the surveillance issue have debated where the line should be drawn between giving the authorities the technological tools they need and protecting the privacy of the public. Mr. Markey is seeking information not only on the legal and policy implications of cellphone surveillance, but also on the financial relationship between police departments and phone carriers - an area that has received little public attention. The Times article, based on 5,500 pages of documents that the American Civil Liberties Union received from 205 police departments, found that cellphone carriers often charged local police departments anywhere from a few hundred dollars for using a cellphone to track a suspect's location, up to $2,200 for a full-scale wiretap of a suspect. The documents showed that police departments routinely used cellphone tracking for both emergency and nonemergency situations, sometimes without getting court warrants. With police policies varying widely, gray areas in the law have given departments wide discretion in determining what types of situations justify phone surveillance and whether court orders are needed. Some departments have even bought their own phone surveillance equipment and bypassed the carriers.