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...