By Esme Murphy

WASHINGTON, D.C. (WCCO) — The investigation into the mass shooting at the Washington Navy Yard continues with no clear motive for why Aaron Alexis opened fire, killing 12 people.

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Alexis was killed in a gun battle with police. He was working at the Navy Yard as an electrical contractor.

On Tuesday, U.S. Secretary of Defense Chuck Hagel laid a wreath at the U.S. Navy Memorial on Pennsylvania Avenue to honor the 12 victims, all civilians who range in age from 43 to 76.

Details have emerged itemizing Alexis’s history of minor run-ins with the law and a checkered career as a Navy reservist that included eight citations for misconduct in just four years.

Despite his troubled history, Alexis managed to get a general discharge from the Navy in 2011; it was apparently that discharge that allowed him to be hired as a contractor and get the necessary security clearance to be working at the Navy Yard.

The FBI searched a Washington-area hotel were Alexis stayed the week before the shooting. They also appealed for information.

“We continue to work to determine where he has been, who he has talked to, and what he has done,” FBI assistant director Valerie Parlave said.

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The Washington Post reports that the offenses Alexis was cited with misconduct by the Navy included insubordination and, in 2008, disorderly conduct after he was arrested and spent two nights in jail for destroying furniture in a Georgia nightclub.

Alexis was arrested two other times in incidents involving a gun but was never charged. In 2004, he shot out another man’s tires in Seattle. In 2010, he shot at the ceiling at his apartment complex in Texas.

Authorities know that Alexis carried out the attack with three weapons — an assault weapon, a pistol and a shogun, which were found by his body.

Friends in Texas say Alexis had recently been upset with the pay he was receiving as a contractor.

One of the victims had Minnesota ties. Janet Hustvet of Shoreview said her 63-year-old sister-in-law Kathy Gaarde was a civilian analyst for the Navy who was ready to retire.

“She was a good mom and a good worker and a good wife who went out of her way to help people,” said Hustvet, who flew to Washington D.C. to be with her brother.

Among the details of Alexis’s background that remain unconfirmed is that Alexis told people he had been traumatized by aiding with the rescue and recovery effort at Ground Zero in New York City after 9/11. His role in the rescue and recovery effort has not been confirmed.

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There is conflicting information, but apparently his security clearance allowed him to drive in to the Navy Yard without his car being checked. That policy of checks and searches in under review right now by the Navy, as is the procedure for obtaining the kind of security clearance that Alexis had, despite his troubled past.

Esme Murphy