- 4 Americans, including its ambassador to Libya, died in a 2012 attack on a mission
- Obama has said that Ahmed Abu Khatallah was "one of the masterminds" of the attack
- Abu Khatallah was nabbed by U.S. commandos, FBI agents this month in Libya
- He's expected to be prosecuted in a federal court in Washington
The suspected mastermind of the deadly 2012 attack on the U.S. mission in Benghazi, Libya, is expected to be brought to American soil as soon as this weekend, a senior law enforcement source told CNN on Thursday.
Ahmed Abu Khatallah was lured earlier this month to a location south of the city in eastern Libya and grabbed without a fight by U.S. commandos and FBI agents, multiple officials said.
He's spent most of the past two weeks aboard the USS New York being interrogated by the FBI-led High Value Detainee Interrogation Group, known as HIG, that includes agents from the FBI, CIA and the Defense Intelligence Agency.
As that vessel -- an amphibious transport dock ship -- nears the coast, it is expected that Abu Khatallah will be flown off of it on a V-22 Osprey aircraft to an undisclosed location, where he will be held as he awaits prosecution in a federal court in Washington.
The Justice Department is expected to announce a formal indictment of Abu Khatallah soon after he arrives in the United States.
Already, a federal judge has unsealed charges accusing Abu Khatallah of killing a person in the course of an attack on a federal facility with a firearm and dangerous weapons, as well as attempting and conspiring to provide material support to terrorists resulting in death.
Abu Khatallah is accused in connection with the September 11, 2012, attack that left U.S. Ambassador Christopher Stevens and three other U.S. citizens dead.
President Barack Obama has described Abu Khatallah as "one of the masterminds of the attack."
"It's a message to the world, that when Americans are attacked, no matter how long it takes, we will find those responsible and we will bring them to justice. Regardless how long it takes, we will find you," the President said earlier this month.
Republicans, though, have hammered Obama and members of his administration on Benghazi -- claiming they didn't do enough to protect the diplomatic mission and have since covered up what happened. Some GOP lawmakers criticized the Justice Department for failing to bring Abu Khatallah to justice even as he taunted U.S. authorities in a meeting with CNN's Arwa Damon at a well-known luxury hotel in Benghazi in May 2013.
Chief among those targeted by Republicans is Hillary Clinton, secretary of state at the time of the attack and now the overwhelming favorite for the 2016 Democratic presidential nomination, if she opts to run. She and administration officials have repeatedly denied the GOP allegations about Benghazi.
After news broke of Abu Khatallah's capture, Clinton said she was "very pleased" and hopefully it will shed more light on what happened.
"I'm still looking for answers," she added. "We're doing our best we can to find out what happened."