Yet the political furor, which now threatens to hold up President Obama’s national security nominations, stands in stark contrast to the response in Libya itself. There, Libyans say, the investigation is nonoperational, if not effectively dead, with witnesses too fearful to talk and key police officers targeted for violent retribution. “There is no Libyan investigation. No, no, no,” says Mohamed Buisier, a political activist in Benghazi, who returned home in 2011 after decades in the U.S. “There is not even a will to investigate anything. Even for us civilians, it is very dangerous if you talk about this subject.”

The growing sense that the culprits in the Sept. 11, 2012 attack might never be caught deepened this week, when Tunisian officials released the sole suspect in custody. Citing lack of evidence, they freed Ali al-Harzi, a Tunisian citizen, though he is still restricted from traveling outside the four governorates surrounding Tunis. Harzi was arrested in Turkey shortly after the consulate attack, and deported to his home country, finally agreeing last month to a three-hour interrogation by FBI agents in Tunis, according to his lawyer Anour Ouled Ali. “He denied everything,” Ali told TIME on Thursday, by phone from Tunis. “He told the FBI he was not involved at all.”

Whoever knows differently is for now not talking. And in fact, they might be dead or missing.