Similar thing happened to a family member of mine and an iPhone 4. It was stolen in a burglary, so I went on Find my iPhone and remotely locked it, and also tracked it to an address about 5 mins walk away. The circle of confidence put it down to one of either two 3 storey flats; Police were informed and they went to the address. They then didn't knock on any doors since 'there were too many flats'. There would have been 6 potential doors. :/
By this time when the Police returned the phone had been turned off. Gutting to say the least.