https://www.bleepingcomputer.com/news/security/distributor-of-the-reveton-police-ransomware-jailed-by-uks-nca/

A key member of a crime group behind the notorious Reveton Police Trojan that locked users out of Windows unless they paid a ransom has now found himself locked up in jail.

In 2012, many Windows users from all over the world suddenly found their computers displaying a message stating that law enforcement has locked them out of their computer due to the distribution of child pornography and copyrighted music, videos, and software. This screen would then prompt the victim to send a MoneyPak, MoneyGram, or Ukash payment in order to unlock the computer.