U.S. Army Staff Sergeant Robert Bales, charged with killing 16 Afghan villagers as they slept, appears in a Washington state military courtroom Monday. TODAY's Natalie Morales reports.

Updated at 6:45 p.m. ET: In pretrial hearings for U.S. Army Sgt. Robert Bales, accused of killing 16 Afghan villagers in a nighttime massacre in March, prosecutors described to a military court on Monday how the sergeant allegedly returned to his base in Kandahar province with the blood of his victims on his rifle, belt, shirt and shoes and then seemed stunned to be confronted by fellow soldiers.

Bales sat quietly in the courtroom at Joint Base Lewis-McChord in Washington state as military prosecutors summarized the events of March 11 when they allege the 39-year-old sergeant walked off his base in Kandahar province under cover of darkness and opened fire on civilians — mostly women and children — in their homes in at least two villages.

Prosecutor Lt. Col Jay Morse said Bales had been drinking and briefly visited the room of a fellow soldier before he left the Army post, called Camp Belambay, and went to a village where he committed the first set of slayings.

Morse said Bales then returned to the camp, told some others what he had done and left again, moving on to a different village and committing additional killings. He called Bales' actions "deliberate, methodical."

The prosecution also showed a video shot by night-vision camera from a surveillance balloon over the camp, showing a figure they identified as Bales walking back to the post wearing what they described as a cape.

The man is seen being confronted by three soldiers, who order him to drop his weapons and take him into custody as he is heard saying, "Are you @!$%#ing kidding me?"

Karilyn Bales, the wife of Army Staff Sgt. Robert Bales, spoke exclusively with NBC's Matt Lauer, telling the TODAY anchor that the news about her husband is 'very unbelievable.'

Cpl. David Godwin, who was among the first to encounter Bales after the alleged shootings, also testified on Monday, describing the meeting as "kind of surreal," the Seattle Times reported.

Godwin, who served under Bales, was one of the people who had been drinking with him on March 10, the night before the killings. He told the court that while they drank, they watched the 2004 movie "Man on Fire," which stars Denzel Washington and is about a CIA operative turned bodyguard who goes on a killing rampage after his child is kidnapped.

After that, Godwin said, he believed Bales went to bed, the Times reported, but learned otherwise when another soldier awakened him at 2 a.m. or 3 a.m., and the two of them went to the post's outer gate looking for Bales. They finally spotted him returning to base sometime before 5 a.m., Godwin told the court.

"I kind of thought that Bob (Bales) thought... he was doing this to better us," said Godwin, according to the Times. He quoted Bales as saying: "I thought I was doing the right thing. I thought I was doing the right thing."

The shooting, which if proven at trial would be the worst civilian slaughter by U.S. forces since the Vietnam War, eroded already-strained U.S.-Afghan ties after over a decade of conflict in the country.

Bales faces 16 counts of premeditated murder and six counts of attempted murder, as well as charges of assault and wrongfully possessing and using steroids and alcohol while deployed. If convicted, he could face the death penalty.

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The hearing is expected to last two weeks and include witness testimony carried by live video from Afghanistan, including villagers and Afghan soldiers. Part of the hearing will be held at night due to the time difference.

At the end, military commanders will decide whether there is sufficient evidence to refer the case for trial by court-martial.

'Sanity board'

Morse said he would present evidence proving "chilling premeditation" on the part of Bales.

John Henry Browne, Bales' civilian lawyer, has suggested that Bales may not have acted alone and may be suffering from post-traumatic stress disorder. Bales is a decorated veteran of four combat tours in Iraq and Afghanistan.

How Staff Sgt. Bales' lawyers are fighting for his life

Bales also has two military defense counselors, Maj. Gregory Malson and Capt. Matthew Aeisi. Malson represented Army Sgt. William Kreutzer, who was sentenced to life in prison three years ago for killing an officer and wounding 18 U.S. soldiers in a 1995 shooting spree during a training session at Fort Bragg, N.C.

Separately, Bales is also subject to a review of his mental fitness to stand trial, often referred to as a "sanity board." The Army has not disclosed the status of that review.

The father of two from Lake Tapps, Wash., appeared with his head shaved, dressed in Army fatigues. He embraced his wife in court before the hearing started.

The investigating officer read the charges against Bales and informed him of his rights. Bales said, "Sir, yes, sir," when asked if he understood them. He was not expected to answer questions in the hearings.

Bales was confined at a military prison in Kansas from March until he was moved in October to Lewis-McChord, where his infantry regiment was based.

Slideshow: Afghanistan: Nation at a crossroads Aref Karimi / AFP - Getty Images More than ten years after the beginning of the war, Afghanistan faces external pressure to reform as well as ongoing internal conflicts. Launch slideshow

The March shooting highlighted discipline problems among U.S. soldiers from Lewis-McChord, which was also the home base of five enlisted men from the former 5th Stryker Brigade charged with premeditated murder in connection with three killings of unarmed Afghan civilians in 2010.

Four of the men were convicted or pleaded guilty in court-martial proceedings to murder or manslaughter charges and were sentenced to prison. Charges against the fifth were dropped.

In August, U.S. Defense Secretary Leon Panetta directed a panel of experts to assess whether reforms were needed in the way the military justice system handles crimes committed by U.S. forces against civilians in combat zones.

Reuters and The Associated Press and NBC News' Kari Huus contributed to this report.

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