Looters who managed to make off with iPhones stolen from Apple stores during the days of civil unrest and rioting over the past week are likely to be in for a surprise.

Apple has begun locking certain iPhones stolen from its stores, making the phones unusable, and has also sent messages to the phones saying that area law officials have been notified about the thefts. An Apple spokesperson confirmed to this news organization that it had begun implementing the security measures for demonstration models of iPhones that it keeps on display for customers to try out at its retail outlets.

Apple wouldn’t say if it was taking similar steps for iPhones that it keeps in supply for customer purchases, saying only, “We don’t comment on matters of security.”

The matter became public when an image of an iPhone began circulating on Twitter with a warning on its screen about the phone being tracked.

“Please return to Apple Walnut Street,” said the message, referring to an Apple store in Philadelphia. “This device has been disabled and being tracked. Local authorities will be alerted.”

Apple didn’t say if it implemented similar security measures for iPads or Mac computers taken from its stores.

Apple had only last week begun opening up some of its stores around the United States after the keeping the locations closed for two months as part of the nationwide effort to slow the spread of coronavirus. Eleven Bay Area Apple stores that had opened for either storefront or curbside sales and service remained closed on Wednesday following several days of riots and violence in the wake of the May 25 killing of George Floyd in Minneapolis by a police officer.