Washington CNN  — 

Former Secretary of State Hillary Clinton has agreed to testify to the House’s select committee investigating Benghazi, the panel’s Democratic ranking member told CNN on Tuesday.

Rep. Elijah Cummings said that Clinton agreed to testify before the committee investigating the 2012 terrorist attack in December after he contacted her months earlier.

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“The chairman asked me back in September to inquire as to whether Secretary Clinton would testify,” Cummings said. “She immediately said she would and that she wanted to come in December, but if December did not work, she would come in January. She said I’ll do it, period. The fact is she was very clear. She did not hesitate for one second.”

The U.S. consulate in Libya was attacked on Sept. 11, 2012. Four Americans, including the U.S. Ambassador to Libya Chris Stevens, were killed. Initially, the attack was thought to be perpetrated by an angry mob responding to a video made in the U.S. which mocked Islam and the Prophet Mohammed, but was later determined to be a terrorist attack.

Nick Merrill, the former first lady’s spokesman, declined to go into detail about why Clinton agreed to testify and when she might do so.

“I’m going to leave it to the committee to address their plans,” said Merrill.

In the past, Cummings has publicly resisted calling Clinton to testify before the committee. The Maryland congressman said in December that he agrees with other Democrats who say they don’t see why she should be called.

Cummings’ comments on Tuesday, however, revealed the clearest indication to date that Clinton was willing to show up before the committee, though many details remain to be agreed upon and the appearance could well never happen.

While touring the country selling her new memoir in June 2014, Clinton was asked whether she would be willing to testify before the House committee.

“We’ll see,” she told NBC in an interview. “I’m not going to prejudge it.”

Clinton added that she took a lot of notes during the attack, but declined to say whether she would hand over the notes.

“Let’s see if it’s on the level or not. I don’t want to be part of anything that in any way politicizes or demeans the sacrifice that we saw happen there,” Clinton said.

The attack has remained a political issue for Clinton, who was secretary of state at the time, since 2012. As the former first lady eyes a potential presidential bid, a number of Republicans have signaled that Benghazi will be a main line of attack against Clinton.

Sen. Rand Paul has said the attack should disqualify Clinton from higher office.

Rep. Trey Gowdy, the chairman of the Benghazi committee, told reporters on Tuesday that he still intends to have Clinton testify as part of the investigation.

SEE: GOP-led report debunks Benghazi theories

“Every witness who has relevant information needs to be talked to,” he said.

But Gowdy is only prepared to hear from Clinton 30 days after receiving “all the [State Department] documents” on the attack, including notes and emails from Clinton.

“We intend to access all of the information necessary to do the job the House instructed us to do,” Gowdy said in his opening statement at a committee meeting on Tuesday. “And we need to access that information now. Talking to only some of the witnesses will not work. Accessing only some of the documents will not work. If you want all of the truth, you need all of the information.”

Republicans have been long urging Gowdy to call Clinton to testify. Stop Hillary PAC, an anti-Clinton group, delivered more than 264,000 signatures to the committee in September 2014 urging Gowdy “to subpoena Hillary in order to uncover the truth about Benghazi and subsequent cover up by the then Secretary of State and President Barack Obama.”

Democrats say that Gowdy and other Republicans have let politics seep into this investigation from the start and decided to call Clinton only after receiving the Stop Hillary PAC signatures. But a statement from the congressman’s spokeswoman calls that into question.

“Chairman Gowdy has always said we look forward to the Secretary’s appearance as soon as practical after State produces documents response to Committee requests,” said Amanda Duvall, Gowdy’s spokeswoman.

Clinton testified for more than five hours before another House committee investigating Benghazi in January 2013, shortly before she left the State Department. At the time, Clinton acknowledged a “systemic breakdown” but said that her department was taking additional steps to increase security at U.S. diplomatic facilities.

Since then, Clinton has said her biggest regret a during the four years she served as America’s top diplomat was the Benghazi attack.

“My biggest regret is what happened in Benghazi,” Clinton said in January 2014. “It was a terrible tragedy losing four Americans, two diplomats and – now it is public so I can say – two CIA operatives.”