Cheryl D. Mills, who served as Hillary Rodham Clinton’s chief of staff while she was secretary of state, said she regrets not thinking more closely about how her boss would handle her e-mail as Clinton was entering the cabinet in 2009.

Mills, a longtime adviser to Clinton who also serves as one of her personal attorneys, said relatively little thought was given to Clinton’s use of a private e-mail account while she was secretary, an issue that is now dogging the Democratic candidate’s presidential campaign.

“If there’s anything I could ever do that would have alleviated this level of attention, certainly I would have wished I could have,” Mills said in a rare interview. “Look, I’m human.”

Mills, 50, has been a member of the Clinton inner circle since she served in the White House Counsel’s office under then-President Bill Clinton and has been a central figure in the e-mail story. It was Mills to whom the State Department first reached out in July 2014 to inquire about gathering Clinton’s e-mails from her time as secretary.

Mills, who has also worked as a personal attorney to the Clintons, helped oversee the process by which Clinton’s e-mails were sorted into work correspondence to be released to the State Department and personal notes to be deleted. But Mills said she did not recall having conversations with the State Department’s legal advisers nor with the agency’s technology staff about the issue.

“I wish there had been a lot more thought and deliberation around it, but I can’t tell you that I can offer you that insight that there was,” she said.

In the interview, Mills declined to say whether she has been contacted by the FBI, which has been investigating the security of Clinton’s e-mail system. Officials have said that Clinton is not a target of the inquiry.

Mills said she wanted to be a “good colleague and a good partner” to the FBI. “We’re continuing to make sure that we are addressing and responding to any of the questions that they are asking,” she said.

Echoing comments from Clinton, she said officials saw her use of a private e-mail account as a continuation of her practice as a senator, when she also used a personal account. They were also aware, she said, that former Secretary of State Colin Powell had at times used a personal account.

Mills testified for nine hours behind closed doors last month in front of the House Select Committee investigating the 2012 attacks on U.S. outposts in Benghazi, Libya. Her interview included questions about Clinton’s e-mail. Committee Democrats have said they plan to release a transcript of the session this week.