My first blog on this is here. I was hoping for reports of forensic evidence, but we do not have new information of that quality. We do not even know if such evidence was even collected. We do not know what sort of investigation of the crime scene was conducted. We have some additional information that is of a different kind.
1. From one report: "The head of the Afghan parliamentary investigation, Sayed Ishaq Gillani, told the BBC that witnesses report seeing helicopters dropping chaff during the attack, a measure used to hide targets from ground attack.
"Gillani added that locals suspect the massacre was revenge for attacks carried out last week on US forces that left several injured."
2. From another report: "President Hamid Karzai is incensed. He's made no secret of the fact that he doesn't believe the US government's story and has accused the US of stonewalling Afghan investigators. Pointing to people who had lost loved ones, he said, 'They believe it's not possible for one person to do that. In one family, in four rooms people were killed, women and children were killed, and they were all brought together in one room and then put on fire. That one man cannot do.'"
For U.S. soldiers and/or mercenaries to burn bodies of their victims in Afghanistan is not unheard of. For example, here is a Reuters report from 2005.
3. From a third report: "Afghan army head General Sher Mohammad Karimi said US military officials 'ignored and blocked' his attempt to investigate the incident. They also prevented Afghan officials from interrogating Bales."
We even have side by side contradictory reports such as this: "One villager, Ali Ahmed, told CNN multiple attackers had come into a home before dawn, asked his uncle where the Taliban were and shot him dead. But another villager, a boy, claimed it was just one person."
On the lone gunman side, there is this report: "The 38-year-old staff sergeant Robert Bales has been depicted as a mentally strained, 'rogue' killer by US and Nato military officials, who have shown Afghan officials surveillance video of his solitary return to base among other evidence that he acted alone."
What is the "other evidence" that he acted alone? It may help to settle the question, but it perhaps can't be released without affecting the rights of the accused.
Whatever the truth of this matter is, the massacre has brought to the surface a huge gulf between the Americans in Afghanistan and the people of the country.
Right now, the U.S. and Afghanistan are in a dispute over the jurisdiction over the accused. The U.S. has acted and removed him to the U.S. Afghanistan wants him back. Was this removal to the U.S. legal under the Status of Forces Agreement?
The author of the linked document (R. Chuck Mason) thinks so. I don't see it that way. He himself writes "Accordingly, U.S. personnel are immune from criminal prosecution by Afghan authorities, and are immune from civil and administrative jurisdiction except with respect to acts performed outside the course of their duties."
Since a massacre is outside the course of his duties, the accused is not immune to criminal prosecution by Afghan authorities, in my opinion.