Along with the 16 counts of premeditated murder, six counts of attempted murder and seven counts of assault, Bales is also charged with illicit use of alcohol and steroids.
The steroid use will be a key factor in Bales' defense, Browne said. "Steroid use is going to be an issue in this case, especially where Sgt. Bales got steroids and how he got steroids," he told CNN last spring.
Bales, who served three tours of duty in Iraq before being sent to Afghanistan, may have been suffering post-traumatic stress disorder, Browne said. Bales suffered a traumatic brain injury during a roadside bomb explosion and lost part of his foot in separate tours in Iraq, he said.
"Anybody that has seen what he's seen and done what he's done at the request of the military -- and I'm not talking about these allegations -- I think would have PTSD. ... Dragging parts of bodies around is not something you forget very often."
Following Afghan tradition, the 16 victims were buried soon after the deaths, before autopsies could be done. Some legal experts have told CNN that could present a difficulty for prosecutors. But there were photographs taken of the victims and survivors who saw it happen. Also, if any rounds were recovered from the scene and matched his weapon, they could be used as evidence against Bales.
The Article 32 hearing, named after the section of the military code of justice that dictates how it works, is sort of a combination of a grand jury hearing and a preliminary hearing in a civilian criminal case. But there are significant differences.
For instance, there will be significant testimony from many of the potential witnesses in the case, and unlike in a grand jury case, Bales and his attorney will be there and be able to cross-examine the witnesses against him or even present witnesses of their own.
This hearing, which is expected to last up to two weeks, will be even more unusual in that the courtroom will be linked by satellite to Afghanistan, where some of the witnesses will testify by teleconference.
On some days, the hearing in Washington state won't even begin until dinnertime, when the day is just beginning on the other side of the world in Afghanistan.
In one other difference from civilian court, the person who acts as the judge in the case will not make a decision about whether the case should go to trial in a court-martial. He or she will make a recommendation to the officer who ordered that the hearing be held. That person will decide which, if any, charges Bales will face at trial and also whether prosecutors will pursue the death penalty in the case.