A Briton was kidnapped, assaulted and imprisoned for four days in west Africa until a ransom was paid for their release, police said today.
The Serious Organised Crime Agency (Soca) said the British national travelled to west Africa to meet someone they had become friends with online - but the friend was the "fictional creation of a criminal group whose sole aim was extorting money".
It was the first reported incident of a person being kidnapped as part of a so-called romance fraud where the victim was British, Soca said.
Soca fraud expert Colin Woodcock said: "Romance frauds are damaging enough, draining people's money and damaging their confidence. But the possibility of kidnap is a sinister development.
"This is a very sensitive subject. People can feel embarrassed at being tricked, or even unwilling to believe that the person they have got to know remotely is a criminal who is after their money.
"We know the networks rely on these responses to reduce the chance that the victim will report the crime, and we are sure there is significant under-reporting by victims as a result.
"In the case of same-sex romance frauds there is the added threat in some countries of laws against homosexuality.
"Criminals use the fear of legal repercussions to make victims feel unsafe in going to the authorities, or even to extort more money. It is a vicious and manipulative crime."
Soca said its anti-kidnap and extortion unit was training local officers on the ground to help them deal with any kidnaps effectively, and work to tackle fraud was also under way in Nigeria and Ghana.