Two Afghan National Army guards testified via a live video stream from Afghanistan, recounting what they had seen in the pre-dawn darkness outside a base the night prosecutors say a U.S. soldier massacred 16 civilians, The Associated Press reports.

One guard recounted that a man had arrived at the base and did not stop even after he asked him three times to do so. Later in the night, the second guard said, he saw a soldier leave the base — laughing as he went.

The guards did not say the soldier was the same person nor did they identify the man as Staff Sgt. Robert Bales, who is accused of carrying out the March 11 attack on two villages near the base in southern Afghanistan.

Prosecutors say Bales broke his shooting rampage into two episodes, attacking one village, returning to the base and then departing again to raid another.

The guards testified at an overnight session of a hearing in Bales' case that will help determine whether he faces a court-martial. Bales could face the death penalty if he is convicted.