Fox News chief intelligence correspondent Catherine Herridge brought us up to date this morning on the latest member of Hillary Clinton's inner circle to testify before the House committee that is investigating the 2012 Benghazi attack.

On Thursday, Cheryl Mills, Clinton's former chief of staff while she was secretary of state, testified for nine hours behind closed doors.

Rep. Trey Gowdy (R-SC), chairman of the Benghazi committee, called the dialogue "professional," but another Republican on the committee criticized Mills for having "memory lapses" on some questions from GOP members.

Today, the committee will hear from Jake Sullivan, who was the deputy chief of staff under Mills at the State Department.

Herridge called Sullivan a "key player" who "had a front row seat as Mrs. Clinton's chief policy adviser during that period."

She said Sullivan, now a top adviser to the Clinton campaign, would have firsthand knowledge of the key decisions made by Clinton before the Sept. 11, 2012 attack and in the immediate aftermath, including:

  1. Placing the consulate in Benghazi without adequate security. 
  2. Failing to heed warnings about an attack being likely in eastern Libya.
  3. Having Amb. Stevens at the facility on September 11.
  4. Blaming an anti-Islam video for triggering the attack. 

Herridge said she has learned from a former military intelligence official that within 24 hours, it was known that the attack was terrorism, including the groups responsible and the names of suspected assailants.

Sullivan's testimony also comes one day after a former Clinton aide said he will invoke the Fifth Amendment before the Benghazi committee and two others.

Bryan Pagliano worked on Clinton's 2008 presidential campaign before helping install her private email server in her New York home.

Watch Catherine's full report above.