A man was sentenced to six years and three months in federal prison March 29 for leading a group that used ATM skimmers to clone debit cards and then used them to withdraw cash, the United States Attorney’s Office said in a statement.

Marius Oprea, 38, a Romanian national, was also ordered to pay nearly $30,000 in restitution. Oprea’s most recent residence was a rental in Port Hueneme, in Ventura County.

The group, which prosecutors called “unusually professional,” targeted the accounts of Bank of America, which issues debit cards for California’s anti-poverty programs, including benefits for the unemployed and disabled.

“[T]he individuals whose accounts are looted most frequently are those who depend on government payments to survive,” an FBI agent that was not identified said in the U.S. Attorney’s Office statement.

ATM skimmers are barely detectable devices that are inserted into the card reader or keypad of an ATM to steal data from credit or debit cards.

Once the victim inserts a card into the ATM, the skimmer reads its information and records it from the card’s magnetic stripe. This information is then used by criminals to create counterfeit cards and use them for unauthorized transactions.

Prosecutors believe Mr. Oprea entered the U.S. illegally and that he came specifically to carry out schemes to steal money from unsuspecting victims by skimming data from ATMs.

“[Oprea] illegally entered our country for one purpose – to take advantage of the weaker ATM security here, which does not require cards containing computer chips,” according to the government’s sentencing memorandum. “He pursued fraud like a full-time job, netting thousands of victims’ accounts.”

Mr. Oprea pleaded guilty last June to one count of conspiracy to commit bank fraud, in which he admitted counterfeit cards were used to withdraw money from the accounts of multiple victims.