Aaron Alexis' erratic and violent behavior was ignored, overlooked or dismissed for nine years by police, the military, the Department of Veterans Affairs and his employer, creating a series of missed opportunities that might have stopped the Washington Navy Yard gunman, according to records and interviews with officials close to the investigation.

The warning signs were stark but never detected or communicated among agencies, allowing Alexis to move freely around military bases with a secret-level security clearance.

Alexis was arrested three times in three states for acts of rash, inexplicable violence. He told Seattle police in 2004, for example, that he had had an anger blackout so intense that he could not recall shooting three rounds from the .45-caliber Glock he usually kept strapped tightly to his waist.