Men in Northern Ireland have been blackmailed over video footage of them performing sex acts.
The victims were duped into recording themselves performing or participating in sex acts and then threatened with their online publication.
Some felt so embarrassed by the so-called "sextortion" that they sent money by wire transfer to accounts in west Africa, police said, adding this usually involved a Western Union transfer to an account in the Ivory Coast.
A PSNI spokesman told the Belfast Telegraph that the crimes had happened in the Newtownabbey, Carrickfergus and Antrim areas.
Detective sergeant Neil Maxwell said there had been an increase in these crimes and they involved men of all ages.
He added: "We want anyone who has been the victim of this type of crime to come forward.
"Do not feel pressurised into paying money as this is unlikely to resolve the issue.
"We are seeing an increase in these types of crime and we can help you.
"Finally, don't do anything online that you wouldn't be prepared to do in public.
"There is no such thing as privacy on the internet and unfortunately there are criminals out there who are only too willing to exploit people for money."
Internet blackmail is increasing across Northern Ireland, with at least two cases reported every week.
In the last six months of 2015, detectives dealt with 62 incidents of cyber blackmail, targeting males of all ages.
The victims, who range from teenagers to men in their 60s, fell prey to criminal gangs based in Nigeria, the Philippines and Ivory Coast.
Scams, which often follow weeks of grooming, involve victims sending indecent or sexually explicit photographs or videos of themselves and then being blackmailed to stop the footage being released to family or friends.
The issue of online blackmail hit the headlines last June when Co Tyrone teenager Ronan Hughes took his own life after what his family described as a "relentless" campaign of bullying by a Nigerian gang.
The 17-year-old, from Clonoe near Coalisland, was duped into posting intimate photos online after receiving pictures of a girl.
He was then blackmailed for £3,000 by criminals who threatened to upload the images to his friends' Facebook pages.
Other cases reported to police since June include a 46-year-old man who was asked to pay £300 to a crime gang in Nigeria, an 18-year-old man who was blackmailed for £300 by someone in the Philippines, and a 28-year-old man who was asked for €9,000 (£6,600) by an extortionist traced to Africa.