Just going from memory, but you should be able to dig up the details in news articles and old posts here (You can always search old posts on https://qresear.ch):
Steinfart's mother sent him to a medical clinic for a brain scan because he was acting crazy and because he was being contacted by the FBI about his online activity. At the clinic, when he was left alone in an examination room, he used a computer in that room to hack the clinic's network. Later he emailed that medical company to blackmail them, something like: he installed malware on their network and they must send him millions of dollars for him to remove it. (Or maybe he said he would shut down their systems or release customer data if they didn't pay him - can't remember.)
I think he was arrested for that, and released on probation, and then arrested again recently when he got caught trying to cheat on his probation's mandatory drug test, by wearing a fake penis dildo thing that contained someone else's urine.