Radar searches of homes illegal and unconstitutional, IU Maurer School privacy expert says

  • Jan. 20, 2015


BLOOMINGTON, Ind. -- USA Today’s revelation today that the FBI, the US Marshals Service and as many as 50 other law enforcement agencies are secretly using sophisticated radar to peer inside private homes is “deeply disturbing,” according to Indiana University Maurer School of Law Distinguished Professor Fred H. Cate.

According to the newspaper, the radars, which have been used for more than two years, work like “finely tuned motion detectors” that can “zero in on movements as slight as human breathing from a distance of more than 50 feet.”

“The Supreme Court has ruled repeatedly that surveillance through the walls of the home, whether by thermal imaging camera, GPS signals or radar, require prior judicial authorization in the form of a warrant,” Cate said.

In Kyllo v. U.S. (2001), the court held specifically that “Where, as here, the Government uses a device that is not in general public use, to explore details of the home that would previously have been unknowable without physical intrusion, the surveillance is a ‘search’ and is presumptively unreasonable without a warrant.”

Radar searches of private homes are therefore both illegal and an unconstitutional invasion of personal privacy, Cate said.

Moreover, in the face of such clear binding precedent, Cate said the failure of law enforcement officials to obtain warrants before deploying radar searches is “further evidence of a pattern of law enforcement officials ignoring both the courts and the law.”

“The urgent desire to track down criminals is understandable and, in fact, laudable. But that must be done consistent with the Constitution.

“At a time when the nation is engaged in a tense debate about police behavior and trust in law enforcement is already being undermined, it doesn’t help to have federal and state authorities ignoring the law,” Cate said.

On Monday, President Barack Obama called for greater government access to encrypted communications based on the promise that the government would only access those communications when authorized by a court to do so. “The timing of today’s revelation is ironic,” Cate said.

And tonight, in Obama's State of the Union address, the president is expected to call for greater information sharing with the government based on the promise that the information will only be used to enhance cybersecurity.

Cate is a senior fellow with the IU Center for Applied Cybersecurity Research and the C. Ben Dutton Professor of Law. He can be reached at 812-855-1161, by email at and on Twitter @fredhcate.

Media Contacts

James Boyd

  • IU Maurer School of Law
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Ken Turchi

Assistant dean for finance and administration

  • Maurer School of Law
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