Seattle defense attorney prepared to meet Monday with Army Staff Sgt. Robert Bales, who is facing formal charges in an attack on two slumbering Afghan villages that left 16 people dead, including nine children.

John Henry Browne flew to Kansas Sunday ahead of his first face-to-face meeting with the 10-year Army veteran, who is being held in an isolated cell at Fort Leavenworth's military prison.

Fort Leavenworth spokeswoman Rebecca Steed said Bales would be able to meet Browne in what is described as a privileged visit. Along with medical visits, such meetings are generally more private than others conducted in the prison.

Bales, 38, hasn't been charged in the March 11 shootings, which have endangered relations between the U.S. and Afghanistan and threaten to upend U.S. policy over the decade-old war.

But formal charges are expected to be filed within a week and if the case goes to court the trial will be held in the United States, said a legal expert with the U.S. military familiar with the investigation.