Authorities arrested the UK security researcher known for stopping the WannaCry ransomware attack in May.

On Wednesday, 22-year-old Marcus Hutchins — also known as MalwareTech — was arrested in Las Vegas for “his role in creating and distributing the Kronos banking Trojan,” according to a spokesperson from the U.S. Department of Justice.

The charges relate to alleged conduct occurring between July 2014 and July 2015.

According to an indictment provided to CNN Tech, Hutchins created the malware and shared it online.

Earlier this year, Hutchins became an internet hero when he helped stop WannaCry, a cyberattack that targeted over 150 countries.

The ransomware locked down computers and demanded $300 to get files back.

Hutchins, who is a malware researcher at the Kryptos Logic security firm, created a killswitch that prevented the spread of the virus.

Friends and family have not been able to speak with Hutchins, according to a person close to the situation. The news of the detention was first reported by Motherboard.

This story is developing.