The first of several former Obama administration officials and former aides to Hillary Clinton is set to be deposed Thursday after a judge ruled in January that they must answer questions under oath about the 2012 Benghazi terror attacks and the Clinton email scandal.

U.S. District Court Judge Royce Lamberth ordered the discovery after a lawsuit was brought by conservative watchdog Judicial Watch, which is seeking to uncover “whether the Benghazi scandal was one reason for keeping Mrs. Clinton’s email secret.”

The conservative group announced Wednesday that Justin Cooper, a former Clinton Foundation adviser who played a role in setting up and administering the former secretary of state’s unauthorized private email server, will answer questions under oath and in-person on Thursday.

Eight other dates for depositions of former Obama officials and Clinton aides were also announced, including Jake Sullivan, a former adviser and deputy chief of staff to Clinton, who will answer questions on April 16.

Other officials do not have to give in-person testimony but are required to answer written questions under oath. Those officials include former United Nations Ambassador and national security adviser Susan Rice, and Ben Rhodes, who served as Obama’s deputy national security adviser.

“Judicial Watch is doing the heavy lifting on the ongoing Clinton email scandal, even as Congress dropped the ball and DOJ and State continued to obstruct our quest for the truth,” Judicial Watch President Tom Fitton said in a statement.

The FBI investigated Clinton's use of the server, hosted in the basement of her home in Chappaqua, N.Y., and while they found Clinton's team was "extremely careless" in handling classified emails, no criminal charges were recommended against anyone involved with Clinton's private email network.