Sen. Elizabeth Warren reprimanded a witness in harshly personal terms Tuesday during a committee hearing, accusing the former regulator of bearing responsibility for the financial crisis and telling him that he had no standing to testify as an expert.

"I am surprised that my Republican colleagues would choose a witness who might have one of the worst track records in history on this issue," Warren said to the witness, Leonard Chanin.

The Massachusetts Democrat, who became known in Washington for confrontational questioning of regulators as part of a financial crisis inquiry, was unusually blunt in Tuesday's hearing, which was called by the Republican majority to examine the costs of overregulation of consumer finance.

Warren began her line of questioning by stating that, as a consumer regulator at the Federal Reserve before the crisis, Chanin had the authority to regulate subprime mortgages and failed. "You did essentially nothing. Your failure had devastating consequences," Warren said.

"Given your track record at the Fed, why should anyone take you seriously now?" she asked Chanin.

When he responded that there was no hard data at the time to suggest that the subprime crisis was brewing, Warren exclaimed, "Did you have your eyes stitched closed?"

She went on to accuse Chanin, who now works at the law firm of Morrison & Foerster, of walking through the revolving door after he left government. Before joining the private sector, Chanin headed the rulemaking team at the Consumer Financial Protection Bureau, the new agency conceived by Warren when she was a Harvard law professor, instituted by the 2010 Dodd-Frank financial reform law, and set up by Warren under an appointment by President Obama.

Warren told Chanin that he was brought in to the consumer bureau, despite misgivings about his tenure at the Fed, because he was the only one who understood the existing rules on consumer financial protections.

"You claimed that you had learned from your failure, but I see today that's obviously not the case," she said.