Law enforcement officers across the country have begun using a hand-held radar device that allows them to effectively see through walls.
While such devices are likely to make a police officer or firefighter's job safer, they are also raising privacy concerns. The American Civil Liberties Union has criticized the use of devices like Range-R from L3 CyTerra, which uses "a highly sensitive Doppler motion detector" to see through most building materials up to 12 inches thick and can detect a person's breathing from 50 feet away.
"They clearly are useful for law enforcement. But just because they are useful doesn't mean they should be unregulated by the law," Nathan Freed Wessler, a staff attorney with the ACLU and an expert on privacy issues.
Wessler said a 2001 Supreme Court ruling determined that police must seek a warrant when using electronic surveillance gear to see through walls. Though that case dealt with infrared cameras, he said radar technology was cited.
"If police wanted to enter my home to conduct search or make an arrest, it has always been clear they would have to get a warrant from a judge first because the home is the most private place we have," Wessler said. "The rule should not be any different because they are using powerful radar gear instead of breaking down my door."
USA Today reported that L3 CyTerra said it has sold about 200 devices to 50 law enforcement agencies at a cost of about $6,000 each. The company did not confirm this to CBS News.
On its website, the L3 CyTerra promotes the device for use by law enforcement agencies, suggesting that it can be used to determine the presence and location of assailants or hostages inside a building prior to entry, locate injured or stranded people inside buildings damaged by earthquakes or flooding, or quickly determine whether people are trapped inside a room or building.
These devices -- which the newspaper said was were first used overseas in Afghanistan and Iraq -- have been introduced quietly and with little fanfare.
However, they have begun to get some scrutiny from the federal courts, with USA Today finding a reference to the device in a December 10th Circuit appellate court decision. A radar device was used to help track down fugitive Steven Denson, who was wanted for parole violations, to a house in Wichita.
The three-judge panel upheld the search. But in its decision, the judges wrote, "we don't doubt for a moment that the rise of increasingly sophisticated and invasive search technologies will invite us to venture down this way again -- and soon."
"It's obvious to us and everyone else in this case that the government's warrantless use of such a powerful tool to search inside homes poses grave Fourth Amendment questions," the judges wrote. "New technologies bring with them not only new opportunities for law enforcement to catch criminals but also new risks for abuse and new ways to invade constitutional rights."
Patrick Rodenbush, a spokesman for the U.S. Department of Justice, said the agency was looking over the court ruling.
"While it is our position to not discuss or disclose any investigative techniques, the Department of Justice is currently reviewing the 10th Circuit Court of Appeals ruling," he told CBS News.