US Army sergeant to face 17 murder counts in Afghan killings
Earlier accounts of the incident, which has damaged U.S.-Afghan relations, had tallied 16 victims, including nine children and three women.
Bales, 38, a four-tour combat veteran, is being held at military detention centre in Leavenworth, Kansas.
His civilian defence attorney, Seattle-based John Henry Browne, was not immediately available for comment.
Earlier this week, Browne said U.S. authorities had no proof of what occurred on the evening in question, and said Bales had "no memory" of the incident.
(Reporting By David Alexander and Bill Rigby; editing by Todd Eastham)