(Reuters) - A U.S. Senate panel on Thursday voted to advance seven of President Joe Biden's first U.S. attorney nominees, including his pick to serve as the top federal prosecutor overseeing the Jan. 6 Capitol riots cases.

The Senate Judiciary Committee signed off on the nomination of Matthew Graves, a former prosecutor now at DLA Piper, to run the U.S. Attorney's Office for the District of Columbia, which has brought more than 600 cases over the riots.

The office has been investigating people who took part in the violence, in which followers of then-President Donald Trump, a Republican, fought police, smashed windows and sent members of Congress and then-Vice President Mike Pence running for safety.

The committee did so unanimously on a voice vote, as it did with the other six. But as a result of a move by Republican Senator Tom Cotton a vote on one of Biden's highest-profile picks, Boston's progressive district attorney Rachael Rollins to serve as Massachusetts' top federal prosecutor, was delayed a week.

Cotton, a conservative from Arkansas, has vowed to block the nomination of Rollins, a criminal justice reformer, whose policies he contends have contributed to a rise in violent crime nationally.

"Rachel Rollins measures success as a prosecutor not by the number of victims she secures justice for, but by the number of criminals she helps avoid consequences," Cotton said in a statement.

Democratic Senator Dick Durbin of Illinois, the committee's chair, said he would schedule a vote on her nomination next week and noted that during the Trump administration, Democrats only moved to delay a vote on three of its 85 U.S. attorney picks.

"These are nominees who are well positioned to serve," Durbin said of the eight lawyers on the day's agenda.

Renee Algarin, a spokesperson for Rollins, in a statement said she "looks forward to the confirmation process and is deeply grateful for the wide range of support her nomination has received."

The panel also voted 13-8 to advance the nomination of Hampton Dellinger , a former Boies Schiller Flexner partner who left in 2020 to start his own firm, to lead the Justice Department's Office of Legal Policy, which advises on nominations for federal judgeships.

Graves from 2007 to 2016 served as a prosecutor in the same U.S. Attorney's Office he would lead, securing a guilty plea from former U.S. Representative Jesse Jackson Jr, a Democrat, for misusing campaign funds, and investigating banks for sanctions violations.

Those sanctions cases resulted in settlements with the U.S. Justice Department and other regulators of $1.45 billion with Germany's Commerzbank and $787.3 million with France's Credit Agricole SA.

He joined DLA as partner in 2016, where his practice has focused on white-collar investigations and helping companies conduct internal probes. The Yale Law School graduate was earlier in his career an associate at WilmerHale from 2002 to 2007.

His clients at DLA have included The Coca-Cola Company, Nike Inc, Bayer AG, and General Electric Co, according to a financial disclosure form.

Read more:

Biden nominates top prosecutors, including one to oversee Jan. 6 riot cases

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(Editor's Note: This story has been updated to include the results of the vote on Hampton Dellinger's nomination.)