WASHINGTON (Reuters) - A CIA operative told a jury on Tuesday about the terror he experienced in 2012 when militants attacked the U.S. diplomatic compound in Benghazi, Libya, and described how he recovered the body of U.S. Ambassador to Libya Christopher Stevens.

The operative, who testified in what the judge described as “light disguise” under the pseudonym “Alexander Charles,” was the latest witness to appear in the trial of Ahmed Abu Khatallah, who is accused of orchestrating the Sept. 11, 2012, attack that killed Stevens and three other Americans.

Charles said “all hell broke loose” shortly after he arrived at the CIA annex in Benghazi, which came under mortar fire. The mortars killed Glen Doherty and Tyrone Woods, and gravely injured two other Americans.

“You could feel the whole ground shaking,” Charles said, describing the attack. “Big blocks of cement (were) falling.”

He added that he thought it would be his “last night on this Earth.” Had the attacks continued, he said, he and the others would have been “buried alive.”

Khatallah was captured in 2014 in Libya by a team of U.S. military and FBI officials and taken to the United States aboard a Navy vessel.

The charges he faces include murder and providing material support to terrorists. Prosecutors say he helped organize the attacks, though he did not physically participate himself.

He has pleaded not guilty.

Since the trial opened last week, jurors have heard emotional testimony from State Department and CIA officials, offering a detailed behind-the-scenes look at what happened that night.

A Bureau of Diplomatic Security agent last week told a harrowing story of how he tried to save Stevens and State Department staffer Sean Smith as they crawled on their bellies through thick black smoke.

On Tuesday, Charles talked about how he helped put Doherty and Woods’ bodies onto a truck waiting outside the annex, and how they worked to save State Department staffer David Ubben, whose leg was nearly blown off.

Because he spoke Arabic, Charles was also able to recover another American’s body, after he said that by “divine intervention,” he overheard a Libyan security official who was standing nearby ask other revolutionaries: “Should we tell him about the dead American in the hospital?”

Charles said he approached the man and asked who he was referring to.

About 15 minutes later, a body was delivered via ambulance in a body bag. Charles said he unzipped the bag, looked down and saw the ambassador’s face.