AFAIK, they arrested him because of the creation and sale/distribution of the Kronos and "UPAS Kit" malware [1]. [1]: https://www.justice.gov/usao-edwi/pr/marc

AFAIK, they arrested him because of the creation and sale/distribution of the Kronos and "UPAS Kit" malware [1]. [1]: https://www.justice.gov/usao-edwi/pr/marcus-hutchins-pleads-guilty-creating-and-distributing-kronos-banking-trojan-and-upas https://www.justice.gov/usao-edwi/pr/marcus-hutchins-pleads-...