Florida authorities made an arrest last month in an alleged multi-state SIM card hacking ring, the latest in a series of similar incidents.

According to court records first unearthed this week by reporter Brian Krebs, law enforcement learned of the plot when a mother in Michigan overheard her son pretending to be an AT&T employee and called investigators. Authorities turned up, searched the son’s room and his computer, and discovered files with a list of names and phone numbers, along with SIM cards and cell phones.

Found seven victims in seven states

After more searching, officers say they discovered SIM cards that led to seven victims in seven states, and who said their identities were stolen and cryptocurrency accounts pilfered of hundreds of thousands of dollars. Officers interviewed the son, who allegedly said about eight others, including a man named Ricky Handschumacher, were involved. According to the officers’ account, Handschumacher discussed the fraud scheme in Discord conversations.

Officers said Handschumacher and others in on the plan would steal personal information, then either impersonate or pay off a cellular service employee to receive a new SIM card with the target’s stolen information. Using that, they could crack any passwords tied to the phone number, including cryptocurrency accounts. Police say Handschumacher told them he had laundered more than $100,000 through cryptocurrency exchanges, although he has pleaded not guilty to the charges.

As Motherboard has documented, the SIM-impersonation technique, sometimes called “SIM-jacking,” is an increasingly popular, dead-simple way for hackers to take over accounts from unsuspecting marks. In another case last month, police say a California man stole millions of dollars in cryptocurrency using the technique.