A look at how the legal process may play out in the case against Ahmed Abu Khattala.

The Libyan militant faces criminal charges connected to the deaths of the U.S. ambassador to Libya and three other Americans from the attack on the U.S. diplomatic compound in Benghazi, Libya, on Sept. 11, 2012. An initial court appearance at the federal courthouse in the nation's capital took place Saturday:

Q: What happened at that court hearing?

A: Abu Khattala pleaded not guilty during a 10-minute appearance before a federal magistrate judge. He was asked whether he understood the charges and he answered "yes" in Arabic. He will remain in custody as the case moves forward.

Q: Who is representing Abu Khattala?

A: A lawyer from the federal public defender's office appeared alongside Abu Khattala.

Q: What is the next step in the legal process?

A: Minutes after Abu Khattala entered his plea, the Justice Department unsealed a two-page grand jury indictment charging him with conspiracy to provide material support to terrorists resulting in death. Attorney General Eric Holder has said Abu Khattala could face additional charges and that federal authorities are working to identify, locate and prosecute additional co-conspirators. The case is in the hands of the U.S. attorney's office in Washington and the Justice Department's National Security Division.

Q: What has been the reaction to the criminal proceedings?

A: The Obama administration supports prosecuting Abu Khattala and other suspected terrorists in American courts, a judicial system that government officials believe is fairer and more efficient than the military tribunal process at Guantanamo Bay, Cuba. But some Republican critics are already raising concerns about the prosecution. Sen. Kelly Ayotte, R-N.H., issued a statement saying "critical intelligence" could be lost in the process of turning Abu Khattala over to the American justice system.