Pelosi spoke as Comey testified before the Oversight panel on why he did not recommend charges against Clinton over use of her home email server.
It is a crime to mishandle classified information, and while Federal Bureau of Investigation director James Comey said on Tuesday there was evidence Clinton or her aides may have broken these laws, there was not enough evidence of criminal intent for a prosecution.
He said during a press conference on Tuesday that while FBI investigators found no "direct evidence" that Clinton's email domain was successfully hacked, he assessed that "it is possible that hostile actors gained access to Secretary Clinton's personal email account".
Clinton could face "administrative sanctions" as a effect of the review, which could mean her loss of security clearance, Fox reported.
Even if the Justice Department wanted to prosecute Hillary, FBI director James Comey's press briefing would have made it hard, if not impossible, to get a grand jury to indict and a trial jury to convict.
On this point, the former secretary of state disagrees. But she repeatedly noted that information later identified as classified was part of correspondence with hundreds of government officials who did not flag any problem.
Separately, the State Department was reopening its internal investigation of possible mishandling of classified information by Clinton and top aides.
"I stand by what I said: I did not send or receive any material marked classified", Clinton told ABC News, in a series of interviews Friday after the shootings in Dallas that also touched on the investigation into her email system.
Cummings and other Democrats criticized the decision by Republicans on the Benghazi panel to conduct an interview next week with a senior Pentagon official who criticized the GOP-led panel for making costly and unnecessary requests. Indeed, House Speaker Paul Ryan, R-Wisconsin, has called on the director of national intelligence to block Clinton's access to classified information while she is a presidential candidate.
During an exchange with Rep. Trey Gowdy, R-S.C., Comey confirmed that the FBI's investigation found at least three emails with classified markings on Clinton's server, despite Clinton's assertion during the Benghazi hearing that she had neither sent nor received any items marked classified.
"I think Director Comey clarified that and certainly the State Department did".
Gowdy complained Thursday that Clinton benefited from a "double-track justice system that is rightly or wrongly perceived in this country". The panel's chairman, Rep. Trey Gowdy, R-S.C., said lawmakers may seek a federal investigation into whether Clinton lied to the committee in testimony previous year.
Pressed by Chaffetz Thursday on whether Clinton lied, FBI Director James Comey said during a hearing that he had not reviewed Clinton's testimony because it had not been referred to him by Congress. Chaffetz assured Comey he would soon get a referral.
Hillary Clinton smiles during a campaign rally, where she received the endorsement of Barack Obama, in Charlotte, North Carolina, July 5, 2016.