A gay man was lured into a meeting through the dating app Grindr and then robbed and threatened with a cattle prod.
Detectives have released CCTV pictures of two men they are hunting in connection with the attack - and warned the culprits could have targeted others.
Scotland Yard said the victim, 26, had been messaging a man through the popular online gay dating app Grindr and invited him round to his home in Bayswater, west London.
When the man, described as blond and in his 20s, arrived he spent most of his time texting on his phone and then announced he was leaving and was escorted out by the victim.
But his accomplice was lying in wait outside wielding a cattle prod, and when the front door opened the pair pounced on the victim, pushing him into his flat.
They threatened him with the cattle prod and stole cash and a laptop computer before fleeing the home in Queensborough Terrace.
The attack happened on Sunday, 28 September at about 5:20pm. Police are asking anyone with information to contact them on 020 7321 7513, or to remain anonymous, call Crimestoppers on 0800 555 111.