By Hugo Gye, Meghan Keneally and Lydia Warren PUBLISHED: 18:56 EST, 12 November 2012 | UPDATED: 18:56 EST, 12 November 2012 A top Democrat has warned that David Petraeus must testify to the Senate about the terror attack in Benghazi - and he could be forced to do so by legal means. Dianne Feinstein insisted it was 'unacceptable' that the former CIA director had not yet given Congress an account of a trip to Libya he made shortly before his resignation last week, and threatened to seek a subpoena to obtain it. Petraeus was due to discuss the CIA's role in the raid which killed the U.S. ambassador and three other Americans before Congress on Thursday.
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Dianne Feinstein threatens to subpoena former CIA director after he pulls out of appointment to give evidence about Benghazi attack
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Replacement will speak instead but Petraeus promises to testify in future
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His alleged mistress Paula Broadwell talked about Libya at college lecture
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Said there were Libyan prisoners in American consulate at the time of the September 11 attack that left four dead including ambassador
Suspicions over how much @placeholder knew about the Benghazi probe could complicate Petraeus' testimony over the controversial issue.