A stolen mobile phone found its way back to its owner after being spotted for sale on eBay.
A 32-year-old Croydon woman was reunited with the gadget, which had been stolen in a town-centre sandwich shop, after police tracked it down on the auction website.
The phone had been put up for sale within hours of being stolen on March 10.
The shop's CCTV failed to record the theft so police were initially unable to identify any suspects.
But officers spotted the phone for sale on eBay and traced the seller to a house in Princess Road, Selhurst.
They interviewed the seller, a 29-year-old woman, who claimed to have found the phone in the town centre.
She provided the police with the details of the phone's buyer and police were able to return it to its original owner on April 17.
The 29-year-old woman was cautioned for theft by finding.
Police looked for the phone on eBay after receiving an alert through CheckMEND, a service that allows people to check whether a registered phone has been reported stolen.
PC Robert Sidney, of the Metropolitan Police's Broad Green Safer Neighbourhood Team, said: "This case highlights two important points. Firstly, if you're buying a phone second-hand or over the Internet, then it is definitely worth checking to see if it has been reported stolen.
"You can do this through the CheckMEND website and whilst there is a small fee, it could save you a lot of money later on.
"Secondly, whether you find a phone or any other expensive item or gadget in the street, then you could be committing an offence by simply keeping it. You should contact police or attend a police station to hand it in.
"If it doesn't get claimed by the owner then it will be given to the finder, but if you just keep it then you could be committing a criminal offence."