General David M. Rodriguez, commanding general of US Army Forces Command, says the shooting of Afghan civilians was a "tragedy" and that the military would hold people accountable.
He was speaking at Joint Base Lewis-McChord, where Army Staff Sergeant Bales was based.
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Armed police have carried out a raid apparently linked to Wednesday's deadly terror attack in Westminster.
Cheryl Grimmer vanished from inside a beach shower block in Wollongong, Australia, in 1970, when she was just three.
Pc Keith Palmer was on the front line and because of his actions, the Westminster attacker was unable to kill anyone else.