Three people were assaulted and robbed in separate incidents after posting items for sale online and meeting the "buyer" in a car park.
Police said each victim agreed to meet their attacker in the McDonald's restaurant car park on Telford Road, Edinburgh, believing it was a genuine buyer.
In all of the cases the people had posted an advert on the Gumtree website to sell Apple computers or phones.
Lothian and Borders Police said they were investigating whether the incidents were linked.
On Monday, a 24-year-old victim arranged to meet the suspect, who said he wished to buy an Apple computer. When they met, the victim was threatened and the man stole the item.
Last month, on January 20, a 31-year-old was wrestled to the ground by the suspect, who stole an iPhone that was for sale.
A 33-year-old was assaulted and an Apple computer stolen in similar circumstances the following day.
Inspector Mark Rennie said: "While no victims were injured, all were understandably distressed as a result of their respective ordeals. We are carrying out inquiries in order to establish whether these incidents are linked.
"At the same time we are warning anyone conducting any transaction over Gumtree or any similar website to take precautions to ensure their safety."
Why are you making commenting on The Herald only available to subscribers?
It should have been a safe space for informed debate, somewhere for readers to discuss issues around the biggest stories of the day, but all too often the below the line comments on most websites have become bogged down by off-topic discussions and abuse.
heraldscotland.com is tackling this problem by allowing only subscribers to comment.
We are doing this to improve the experience for our loyal readers and we believe it will reduce the ability of trolls and troublemakers, who occasionally find their way onto our site, to abuse our journalists and readers. We also hope it will help the comments section fulfil its promise as a part of Scotland's conversation with itself.
We are lucky at The Herald. We are read by an informed, educated readership who can add their knowledge and insights to our stories.
That is invaluable.
We are making the subscriber-only change to support our valued readers, who tell us they don't want the site cluttered up with irrelevant comments, untruths and abuse.
In the past, the journalist’s job was to collect and distribute information to the audience. Technology means that readers can shape a discussion. We look forward to hearing from you on heraldscotland.com
Comments & Moderation
Readers’ comments: You are personally liable for the content of any comments you upload to this website, so please act responsibly. We do not pre-moderate or monitor readers’ comments appearing on our websites, but we do post-moderate in response to complaints we receive or otherwise when a potential problem comes to our attention. You can make a complaint by using the ‘report this post’ link . We may then apply our discretion under the user terms to amend or delete comments.
Post moderation is undertaken full-time 9am-6pm on weekdays, and on a part-time basis outwith those hours.
Read the rules hereComments are closed on this article