Most of the testimony, however graphic, was circumstantial, pointing to a lone American gunman but not directly implicating Sergeant Bales. The villagers testified on the fifth day of a military proceeding known as an Article 32 investigation, held to establish whether there is enough evidence to bring Sergeant Bales before a court-martial. If a court-martial is ordered and the Army decides to continue the prosecution as a capital case, the sergeant could face the death penalty.

Sergeant Bales, a decorated veteran of three tours in Iraq before being sent to Afghanistan last December, was deployed from Joint Base Lewis-McChord. He was held at the military prison at Fort Leavenworth in Kansas before being brought here for the hearing.

Witnesses earlier in the week talked about the blood-soaked clothes that Sergeant Bales was seen wearing when he returned to his base in Kandahar and his comments to fellow soldiers about having done “the right thing.” There was also testimony about the test for steroids in his system that came back positive three days after the killings.

The hearing’s night sessions, which were scheduled to continue on Saturday, were all about the violence that unfolded the night of March 11. Mr. Adin, who was summoned to his cousin’s compound by a telephone call early the next morning, told of boot prints that were on some bodies, including the head of a child who had apparently been shot and stomped or kicked. Mr. Adin talked about a small child who he said appeared to have been “grabbed from her bed and thrown on the fire.” But Mr. Adin never saw the gunman, arriving after the fact.

Another witness, a boy named Sadiquallah, who said he was “around 13 or 14,” ran with another boy and hid behind some curtains in a back room. Sadiquallah said he had seen a man with a gun and a light, but had been more intent on hiding than looking around.

Image Sergeant Bales, left, training at Fort Irwin in California half a year before 16 Afghans were killed. Credit... Reuters

“In that room where I was hiding behind the curtains, a bullet hit me,” he said. The bullet struck one of his ears, but he said he had not heard the gunfire. The boy hiding with him was wounded as well, Sadiquallah said.