By Eric Lichtblau
A former aide to Hillary Clinton when she was secretary of state testified behind closed doors for two hours Wednesday in the first in a series of depositions that are likely to raise more questions about Mrs. Clinton’s use of a private email server just as she prepares for an election campaign against Donald J. Trump.
The former aide, Lewis A. Lukens, testified under oath about his knowledge of Mrs. Clinton’s private email system as part of a lawsuit brought against the State Department by a conservative legal advocacy group, Judicial Watch.
At least five other officials — including two of Mrs. Clinton’s top aides at the State Department, Cheryl Mills and Huma Abedin — are also scheduled to testify in the lawsuit over the next six weeks in what promises to be an unwelcome distraction for the Clinton campaign.
The last deposition is set for June 29 — less than a month before the start of the Democratic National Convention in Philadelphia, where Mrs. Clinton is widely expected to win her party’s nomination for president over challenger Bernie Sanders.
Meanwhile, the F.B.I. is continuing to investigate the issue of Mrs. Clinton’s private email server to determine whether any federal laws regarding the handling of classified material or other issues may have been broken.
James Comey, the F.B.I. director, told reporters last week that he would not let the campaign calendar dictate the schedule for his agency’s investigation. The Justice Department will ultimately make any decision on charges.
The F.B.I. has already interviewed both Ms. Abedin and Ms. Mills, and it is also expected to speak with another former aide, Jake Sullivan, officials said.
Mrs. Clinton herself has offered to sit down with the F.B.I. in the email case, and that interview – which is sure to generate enormous political and legal attention — could come in a matter of weeks.
Judicial Watch sued the State Department under the Freedom of Information Act for records relating to Ms. Abedin’s special employment status at the State Department under Mrs. Clinton, who was also a close friend. The legal affairs group has been a frequent antagonist of both Hillary and Bill Clinton over the years.
After The New York Times reported last year that Mrs. Clinton had used a private email account exclusively during her entire tenure at the State Department, a federal judge in the lawsuit allowed Judicial Watch to conduct discovery and gather evidence about how the private email server was created at the State Department.
The judge, Emmet G. Sullivan of United States District Court in Washington, has been sharply critical of the State Department’s handling of the email affair over the last year.