WASHINGTON — Hillary Rodham Clinton’s personal lawyer has told a Senate committee that emails and all other data stored on her computer server were erased before the device was turned over to federal authorities.

In a letter sent last week to Sen. Ron Johnson, R-Wis., the chairman of the Senate Homeland Security Committee, attorney David Kendall said the server was transferred to the FBI on Aug. 12 by Platte River Networks, a Denver firm hired by Clinton to oversee the device. The Senate committee made Kendall’s letter public on Wednesday. In exchanges with reporters earlier this week, Clinton said she was not aware if the data on her server was erased.

Federal investigators, prompted by a request from the inspector general for the State Department, requested custody of the server to learn whether the data stored on it was secure. NBC News has reported that an FBI team is now examining the server. Forensics experts told The Associated Press this week that some emails and other data may still be extracted from servers even after they are supposedly expunged.

Separately, John Podesta, Clinton’s campaign chairman, told reporters Wednesday in Columbia, South Carolina that, to his knowledge, no other copy had been made of the server’s contents other than those her lawyers turned over to the FBI.

As campaign officials answered questions, one of Clinton’s rivals said the email issue has become a distraction for the Democratic Party.

“I think that it’s a huge distraction from what we should be talking about as a party,” former Maryland Gov. Martin O’Malley told reporters in Nevada.

Instead, he said more debates should be held among the candidates to address raising the minimum wage, repairing the country’s infrastructure and other issues. “Until we do, our party’s label is going to be the latest news du jour about emails and email servers and what Secretary Clinton knew and when she knew it.”

O’Malley said some people in the Democratic National Committee are “circling the wagons.”

Kendall said in his letter to the committee that both he and another lawyer at his firm were given security clearances by the State Department to handle a thumb drive that contained about 3,000 emails later turned over to the agency.