Ahmad Abu Khatallah, the alleged Benghazi ringleader, was on Saturday brought to DC to be tried in connection with the killing of US ambassador to Libya and three others in 2012.
Khatallah, who faces charges of conspiracy and providing material support to terrorists, according to an earlier indictment, pleaded not-guilty thorough a public defender.
Snatched from a seaside resort on June 15 special forces, Khatallah had been held on a US navy ship for interrogation. He is said to be cooperating, according to reports.
US ambassador to Libya J Christopher Stevens, two CIA operatives and a foreign service official were killed in an attack on their mission in Benghazi on September 11, 2012.
The incident quickly turned political with Republicans attacking President Obama, who was then running for a second term, accusing him of not doing enough to prevent it and stop it.
The president also faced criticism, even from those in his his party, in subsequent months for not delivering on his promise of catching those responsible for the attack.
“Now that Ahmed Abu Khatallah has arrived in the United States, he will face the full weight of our justice system,” said US attorney general Eric Holder.
“We will prove, beyond a reasonable doubt, the defendant’s alleged role in the attack that killed four brave Americans in Benghazi.”
Appearing before a DC judge amid tight security on Saturday, Khatallah, who has been assigned a public defender, pleaded not-guilty to the charges.
Legal experts have said they believe getting a guilty conviction will be tough. FBI investigators, for one, were not able to visit the crime site for weeks because of security concerns.
Witnesses who may be brought in from Libya to testify against him may not be able to withstand cross-examination.
But the justice department appeared confident of its case.