https://motherboard.vice.com/en_us/article/ywp8k5/researcher-who-stopped-wannacry-ransomware-detained-in-us-after-def-con

On Wednesday, US authorities detained a researcher who goes by the handle MalwareTech, best known for stopping the spread of the WannaCry ransomware virus.

In May, WannaCry infected hospitals in the UK, a Spanish telecommunications company, and other targets in Russia, Turkey, Germany, Vietnam, and more. Marcus Hutchins, a researcher from cybersecurity firm Kryptos Logic, inadvertently stopped WannaCry in its tracks by registering a specific website domain included in the malware's code.