More than 30 purported street gang members have been charged with stealing more than $1 million in what authorities said Monday was an unusually sophisticated credit card fraud scheme.

Members and associates of the BullyBoys and the CoCo Boys street gangs based in the suburbs east of San Francisco defrauded hundreds of victims by breaking into dozens of medical and dental offices to steal credit card terminals and patient records, said state Attorney General Xavier Becerra and police chiefs from three cities.

The 32 alleged gang members used the stolen terminals to process credit card returns, downloading them to debit cards, according to the 240-count indictment.

"It is easier today and it is more rewarding today to engage in identity theft and financial fraud than it is to go out there on the street and commit physical, violent crime," Becerra said. "It pays more at lower risk," though he alleged the gangs used the money to fund other illegal activities that are not included in the indictment.

Defense attorneys did not immediately return messages seeking comment.

The investigation began in early 2016 when investigators noticed similarities between burglaries scattered across Northern California.

The indictment handed down last month by a special Sacramento County-based statewide grand jury includes counts of conspiracy to commit grand theft; hacking, computer access and fraud; grand theft; burglary; and identity theft.

"It may not be as physically harmful and dangerous as being accosted on the street, but I can guarantee you it hurts just as much" Becerra said.

Nearly 130 law enforcement officers fanned out last week to make 23 arrests, said Walnut Creek Police Chief Tom Chaplin. Another two were arrested over the weekend, while seven remain fugitives, said Deputy Attorney General Tawnya Austin, who heads the attorney general's e-crimes unit.

Investigators recovered about 40 stolen credit card terminals, dozens of fraudulent receipts, laptop computers and files including Social Security numbers or bank information.

Street gangs have become more mobile, picking targets over large regions and taking advantage of opportunities like unsecured or unencrypted files or financial equipment, said Sacramento Police Chief Daniel Hahn.

"We've all seen high tech crime become the new battleground," said Chaplin.