Authorities believe Aaron Alexis acted alone in a shooting at the Washington Navy yard that left 13 dead and eight injured. Alexis had a 'history of misconduct' with the Navy and was arrested for two past shooting incidents.

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  Police believe Navy vet with arrest history acted alone in DC massacre

  Authorities believe Aaron Alexis acted alone in a shooting at the Washington Navy yard that left 13 dead and eight injured. Alexis had a 'history of misconduct' with the Navy and was arrested for two past shooting incidents.
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