More than 100 iPhones have been found in a single backpack after people at the Coachella music festival in California tracked their missing handsets, local police have said.
Revellers had used the Find My iPhone app, which shows the location of a linked phone on laptops or other devices, Indio Police said.
And a suspect had then been "followed" through the site and detained.
Several phones had been returned immediately, the police added.
And the rest had been handed to lost property at the festival site.
Police had already dedicated extra resources to the festival after "chatter on social media" about missing iPhones, Sgt Dan Marshall told tech news site Gizmodo.
But "in this case, the fans came through".
Festival-goers have been advised to:
- keep valuables in front rather than back pockets
- ensure all valuables are not kept together
- carry a dummy wallet to fool thieves