Politicians have seen a video made drone surveillance and security camera video that showed them in real time the attack in Libya that killed four Americans, including the ambassador.
Top intelligence officials showed them the footage as part of hearings on the attack in September on the diplomatic mission in Benghazi.
Senate intelligence Committee Chairman Dianne Feinstein and ranking member Saxby Chambliss said they will hold at least two more fact-finding hearings before a public session to share what they have learned.
Neither would say if they are satisfied with explanations of why the intelligence analysis changed, from reports that a demonstration turned violent, to blaming the attack on terrorists alone.
The senators said they hope to hear more details when ex-CIA Director David Petraeus testifies behind closed doors on Friday.