Facebook and Gumtree fraudsters are abusing the social networking sites to steal from residents, say Lambeth police.

Cops are warning cyber surfers to take precautions when selling or buying items on the internet, after a string of incidents that resulted in robberies.

Last week in Clapham a man was mugged by people he was meeting for the first time after befriending them on Facebook.

And on April 13, Anthony Thompson, 21, and a 17-year-old ,who cannot be named for legal reasons, were jailed at Inner London Crown Court for a total of six-and-a-half years, for setting up a violent pre-planned robbery after moonlighting as second-hand watch sellers on Gumtree.

Their 15-year-old accomplice was given a two-year supervision order and was electronically tagged.

The trio lured a man who regularly sold watches on Gumtree, and his girlfriend, to a Brixton flat on November 12 last year. The couple believed they were meeting a man who would sell them a Rolex watch.

Up to four men attacked them in the stairwell of the block in Cotton House, strangling the man with a chain, and stealing £2,300 cash from his girlfriend at knifepoint.

The men - who all pleaded guilty to robbery - were later caught by police with some of the stolen cash and the dog chain.

Detective Inspector Andy Christopher, who led the investigation, called it a crime that would change the lives of the two innocent victims forever.

He added: "If you are going to buy or sell anything using internet sites, arrange to meet the seller, always go with someone, and meet in a public place such as a cafe where there are many people about.

"Do not be tricked into going to a second location, even if it is very close by."

Have you been the victim of cyber crime? Email newsdesk@streathamguardian.co.uk or call 020 8330 9538.