Officers in Indiana found a number of cell phones at the scene of a drug bust, and searched each phone for its telephone number. Having the numbers allowed the government to subpoena the owners’ call histories, linking them to the drug-selling scheme.

One of the suspects, Abel Flores-Lopez, who was convicted and sentenced to 10 years in prison, argued on appeal that the police had no right to search the phone’s contents without a warrant.

The case gave the 7th Circuit an occasion to examine just how far police can go when it comes to searching electronic gadgets.

“Lurking behind this issue is the question whether and when a laptop or desktop computer, tablet, or other type of computer (whether called a ‘computer’ or not) can be searched without a warrant,” Judge Richard Posner wrote for the three-judge panel.