They named the suspect as he was heading back to the US to face charges.
Robert Bales has now arrived at a maximum security military prison in Fort Leavenworth, Kansas, after being flown from Kuwait, the US Army said.
The suspect will be held in solitary confinement pending charges, the Army added.
Sgt. Robert Bales’ lawyer, John Henry Browne, said he had been injured twice while serving in Iraq.
John Henry Browne also said the accused, aged 38, had witnessed his friend’s leg blown off the day before the killings.
That incident has not been confirmed by the US Army.
The Taliban called off peace talks in the wake of Sunday’s deadly rampage – in which men, women and children were shot and killed at close range.
The US has stressed it remained committed to Afghan reconciliation.
Afghan President Hamid Karzai has also reacted angrily to the killings. He told the US it must pull back its troops from village areas and allow Afghan security forces to take the lead in an effort to reduce civilian deaths.
On Friday he said the US was not fully co-operating with a probe into the killings.
He also said the problem of civilian casualties at the hands of Nato forces had “gone on for too long”.
“This form of activity, this behaviour cannot be tolerated. It’s past, past, past the time,” Hamid Karzai said.
Shortly after Sgt. Robert Bales’ name emerged, John Henry Browne confirmed that was the name of the soldier he was representing.
The photos were soon removed from the live site but remained available to access.
Sgt. Robert Bales has not yet been charged, but is the only known suspect in the killings – despite repeated Afghan assertions that more than one American was involved.
The Pentagon has previously said that he could face charges that carry a possible death penalty.
Such a trial could take years, contrasting with Afghan demands for swift and decisive justice.
In the town of Lake Tapps, Washington state, neighbors described their surprise at Sgt. Robert Bales’ alleged crimes.
Speaking in Seattle on Thursday, where Sgt. Robert Bales is based at Joint Base Lewis-McChord, John Henry Browne said his new client was a “mild-mannered” man who bore no antipathy towards Muslims.
John Henry Browne described him as “a decorated soldier” who had an exemplary record before the shooting.
The lawyer also suggested the soldier, who began his first deployment to Afghanistan in December, was not fit to serve because of injuries he had suffered on previous tours of duty.
John Henry Browne said that a car accident caused by a roadside bomb in Iraq had given the soldier a concussive head injury. Part of his foot had also been removed in surgery because of a battle-related wound, he added.
“I think it’s of interest that we have a soldier who has an exemplary record, a decorated soldier who was injured in Iraq, to his brain and to his body and then despite that was sent back,” he said.
John Henry Browne, who has represented a number of high-profile clients including serial killer Ted Bundy and a teenage thief known as the Barefoot Bandit, said his client was a happily married man with two children, aged three and four.
The US House Ethics Committee has voted to release its report on former Republican Representative…
ABC News has agreed to pay $15 million to President-elect Donald Trump to settle a…
South Korea’s parliament has voted to impeach President Yoon Suk Yeol over his failed attempt…
Israeli war planes have carried out more than 100 air strikes in Syria on December…
President-elect Donald Trump has threatened to impose 100% tariffs on the BRICS countries if they…
Syrian troops have withdrawn from the city of Aleppo following an offensive by rebels opposed…