Prosecutors in California have reportedly won what they believe to be the first-ever conviction for the act of SIM hijacking.

Joel Ortiz, a 20-year-old college student from Boston, pleaded guilty in a Santa Clara County courtroom last month to stealing over $5 million in cryptocurrency after taking over the phone numbers of roughly 40 individuals with the help of unnamed accomplices, Motherboard has reported.

Ortiz was sentenced to 10 years in prison for his SIM swapping spree, which involved tricking mobile carriers into transferring targeted victims’ phone numbers to SIM cards controlled by the criminal. After seizing possession of these numbers, Ortiz would then use them to reset victims’ email accounts, and access and steal from their cryptocurrency wallets. A member of OGUSERS, a forum for trading stolen user accounts, Ortiz would also overtake his victims’ social media accounts in hopes of selling them for Bitcoin.

He reportedly targeted individuals working in the fields of cryptocurrency and blockchain, in some cases attacking individuals during the related Consensus conference in New York last May.

Authorities arrested Ortiz last July before he was able to catch a flight to Europe. He was soon after charged with multiple counts of identity theft, hacking and grand theft charges.