WASHINGTON (AP) — Government witnesses in the trial of Ahmed Abu Khattala testified Tuesday in graphic detail about the bloody attacks on U.S. compounds in Benghazi, Libya, while defense attorneys worked to raise doubt that the defendant masterminded the 2012 strikes that killed four Americans.

The trial entered its second day with U.S. government prosecutors questioning diplomatic security agent Scott Wickland, who tried unsuccessfully to save ambassador Chris Stevens and Sean Patrick Smith, a State Department information management officer, from a burning U.S. diplomatic outpost. Nearly eigh...