Should this be allowed to fight crime and terrorism?

Armed with new technologies, including mobile devices that tap into cellphone data in real time, dozens of local and state police agencies are capturing information about thousands of cellphone users at a time, whether they are targets of an investigation or not, according to public records obtained by USA TODAY and Gannett newspapers and TV stations. The records, from more than 125 police agencies in 33 states, reveal: About one in four law-enforcement agencies have used a tactic known as a "tower dump," which gives police data about the identity, activity and location of any phone that connects to the targeted cellphone towers over a set span of time, usually an hour or two. A typical dump covers multiple towers, and wireless providers, and can net information from thousands of phones. At least 25 police departments own a Stingray, a suitcase-size device that costs as much as $400,000 and acts as a fake cell tower. The system, typically installed in a vehicle so it can be moved into any neighborhood, tricks all nearby phones into connecting to it and feeding data to police. In some states, the devices are available to any local police department via state surveillance units. The federal government funds most of the purchases, via anti-terror grants. Thirty-six more police agencies refused to say whether they've used either tactic. Most denied public records requests, arguing that criminals or terrorists could use the information to thwart important crime-fighting and surveillance techniques. Police maintain that cellphone data can help solve crimes, track fugitives or abducted children or even foil a terror attack. Organizations such as the American Civil Liberties Union and Electronic Privacy Information Center (EPIC) say the swelling ability by even small-town police departments to easily and quickly obtain large amounts of cellphone data raises questions about the erosion of people's privacy as well as their Fourth Amendment protections against unreasonable search and seizure. "I don't think that these devices should never be used, but at the same time, you should clearly be getting a warrant," said Alan Butler of EPIC. In most states, police can get many kinds of cellphone data without obtaining a warrant, which they'd need to search someone's house or car. Privacy advocates, legislators and courts are debating the legal standards with increasing intensity as technology — and the amount of sensitive information people entrust to their devices — evolves. Many people aren't aware that a smartphone is an adept location-tracking device. It's constantly sending signals to nearby cell towers, even when it's not being used. And wireless carriers store data about your device, from where it's been to whom you've called and texted, some of it for years. The power for police is alluring: a vast data net that can be a cutting-edge crime-fighting tool. In October 2012, in Colorado, a 10-year-old girl vanished while she walked to school. Volunteers scoured Westminster looking for Jessica Ridgeway. Local police took a clandestine tack. They got a court order for data about every cellphone that connected to five providers' towers on the girl's route. Later, they asked for 15 more cellphone site data dumps. Colorado authorities won't divulge how many people's data they obtained, but testimony in other cases indicates it was at least several thousand people's phones. The court orders in the Colorado case show police got "cellular telephone numbers, including the date, time and duration of any calls," as well as numbers and location data for all phones that connected to the towers searched, whether calls were being made or not. Police and court records obtained by USA TODAY about cases across the country show that's standard for a tower dump. The tower dump data helped police choose about 500 people who were asked to submit DNA samples. The broad cell-data sweep and DNA samples didn't solve the crime, though the information aided in the prosecution. A 17-year-old man's mother tipped off the cops, and the man confessed to kidnapping and dismembering the girl, hiding some of her remains in a crawl space in his mother's house. He pleaded guilty and last month was sentenced to more than 100 years in prison. Not every use of the tower dumps involved stakes so high.