JOINT BASE LEWIS-MCCHORD, Washington — Prosecutors called Tuesday for a US soldier accused of killing 16 Afghan villagers to face a full court martial and possible death sentence, as a pre-trial hearing ended.

But the family of Sergeant Robert Bales insisted he was innocent until proven guilty, calling him "courageous and honorable," while his lawyer raised questions about the role of alcohol, drugs and stress in the tragedy.

Wrapping up the case, prosecutors lashed the "brutality" of the alleged massacre in March, outlined during an eight-day hearing at a military base south of Seattle.

"Based on the sheer brutality and nature of the crimes, it is our recommendation to proceed to a general court martial," said prosecutor Major Rob Stelle at Joint Base Lewis-McChord.

He said there were two main reasons why the case should go to a court martial, namely that "something horrible happened" on the night of March 11, and that Bales was clearly aware of what he had done.

"The most telling evidence we have are the statements made by Sergeant Bales in the few hours (after the incident) -- statements that demonstrate a clear memory of what happened and a clear sense of guilt," said Stelle.

Bales faces 16 counts of murder, six of attempted murder, seven of assault, two of using drugs and one of drinking alcohol. Seventeen of the 22 victims were women or children and almost all were shot in the head.

The 39-year-old allegedly left his base in the Panjwayi district of Kandahar province on the night of March 11 to commit the killings, which included nine children. He allegedly set several of their bodies on fire.

Prosecutors at the so-called Article 32 pre-trial hearing have alleged that Bales left the base twice to carry out the killings, returning in between and even telling a colleague what he had done.

But Bales' lawyer Emma Scanlan questioned Tuesday whether there was enough evidence for the case to go to full trial, citing possible Post-Traumatic Stress Disorder (PTSD) and other medical issues.

"The question now is whether you have enough information to go forward," she said.

"There are a number of questions that have not been answered in this investigation... We have been told that Sergeant Bales was 'lucid, coherent, and responsive.' But we don't know what it means to be on alcohol, steroids, and sleeping aids."

The hearing was held to decide if Bales should face a full court martial. Investigating Officer Colonel Lee Deneke said he would submit a written recommendation "later this week or over the weekend." A three-star general at the base will then rule on whether to proceed with a court martial.

In a family statement read out by Bales' sister Stephanie Tandberg after the hearing, they said: "We all want very much to know how, why, and what happened ... the article 32 hearing is over, and we still don't know.

"Much of the testimony was painful, even heartbreaking, but we are not convinced the government has shown us the truth, the whole truth, and nothing but the truth about what happened that night."

She continued: "As a family, we all grieve deeply for the Afghani families who lost their loved ones on March 11, but we must all not rush to judgment.

"In America, due process means innocence is always presumed unless and until a trial proves otherwise. There has been no trial yet, and our family member is presumed by law, and by us, to be innocent.

"We know Bob as bright, courageous and honorable, as a man who is a good citizen, soldier, son, husband, father, uncle and sibling. We and Bob's family are proud to stand by him."