PRIVACY: Fourth Circuit adopts mosaic theory, holds that obtaining “extended” cell-site records requires a warrant. “In the new opinion, the Fourth Circuit (Judge Davis joined by Judge Thacker, with Judge Motz dissenting) holds that ordering a cell provider to hand over ‘extended’ records is a Fourth Amendment search because ‘society recognizes an individual’s privacy interest in her movements over an extended time period.’ The Fourth Circuit relies primarily on the ‘mosaic theory’ arguments of the D.C. Circuit’s opinion in United States v. Maynard and the concurring opinions when that case reached the Supreme Court under the name of United States v. Jones.”

UPDATE: I had some related thoughts here.