The Washington Navy Yard is reopening to workers three days after it a mass shooting in which a gunman killed 12 people.

Workers return the Washington Navy Yard
Workers return the Washington Navy Yard following shooting (WRC TV)
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Gates at the Navy installation reopened at 6 a.m. Thursday.

But traffic was blocked from reaching the main gate because a tractor-trailer tried to make a U-turn, and its load shifted. The truck was blocking the road in front of the Navy Yard early Thursday.

Navy spokeswoman Lt. Cmdr. Sarah Flaherty said Thursday will be a regular work day, except for Building 197, where the shootings occurred, and the base gym. She says the gym is being used as a staging area for the FBI to investigate Monday's rampage in which former Navy reservist Aaron Alexis gunned down 12 people before being killed by police.

Investigators are still trying to determine a motive for the shooting. They have been focusing on the erratic behavior of a former Navy reservist who law enforcement officials say was grappling with paranoia and had reported hearing voices in recent weeks.

The Department of Veterans Affairs said Wednesday that 34-year-old Aaron Alexis visited two hospitals in the weeks before the Monday morning rampage but denied he was depressed or having thoughts of harming himself or others.

Alexis, who died in a police shootout after the rampage, complained of insomnia during an Aug. 23 emergency room visit to the VA Medical Center in Providence, R.I. He was given sleep medication and advised to follow up with a doctor. He made a similar visit five days later to the VA hospital in Washington.

(Copyright 2013 The Associated Press. All Rights Reserved)

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