Updated

More than three weeks after the massacre of 17 civilians in Afghanistan, U.S. military investigators finally have gotten their first look at the villages where Army Staff Sgt. Robert Bales allegedly carried out the shooting rampage.

Army criminal investigators visited the villages early this week to collect forensic evidence, two senior defense officials said Thursday. The officials spoke on condition of anonymity because of prohibitions against talking about the ongoing investigation into the March 11 killings.

Investigators stayed away from the shooting sites for more than three weeks to avoid aggravating tensions with angry villagers.

It was not known how much or what kind of evidence they were able to find so long after the shootings.

Bales has been charged with 17 counts of murder and is being held in a U.S. military prison in Kansas.

After meeting with Bales last month for the first time, his lawyer, John Henry Brown, questioned the quality of the evidence against his client.

"I don't know about the evidence in this case. I don't know that the government is going to prove much. There's no forensic evidence. There's no confessions," Browne said.

"I'm certainly not saying that we're not taking responsibility for this in the right way, at the right time. But for now, I'm interested in what the evidence is," Browne said. "It's not like a crime scene in the United States."

Afghan officials have been to the villages to investigate the incident. And guards have said they saw Bales leave his military base, return and then leave again.

Investigators also have collected information from other troops at the base.

Bales, 38, a father of two, is accused of walking off the base where he was deployed in southern Afghanistan with a 9 mm pistol and M-4 rifle outfitted with a grenade launcher. Officials say Bales walked to two local villages, killing four men, four women, two boys and seven girls, then burned some of their bodies.