Millions of adult dating website users' details leaked online
Almost 4 million of Adult Friend Finder's users have had personal information, including sexual preferences, leaked online.
The BBC are reporting that the California based company have contacted the police after they discovered the hack.
In a statement the company said: "FriendFinder Networks Inc. has only just been made aware of this potential issue and understands and fully appreciates the seriousness of the issue."
"We have already begun working closely with law enforcement and have launched a comprehensive investigation with the help of leading third-party forensics expert, Mandiant.
"Until the investigation is completed, it will be difficult to determine with certainty the full scope of the incident, but we will continue to work vigilantly to address this potential issue and will provide updates as we learn more from our investigation.
"We cannot speculate further about this issue, but rest assured, we pledge to take the appropriate steps needed to protect our customers if they are affected."
Channel 4 news say that 3.9million user details were leaked, with details such as e-mail addresses, names, age and sexual preferences among the data. It is feared that the leak may have happened two months ago but was only discovered in recent days.
The site has 40 million members worldwide