Navy Yard shooting: Authorities confident only one gunman involved

Seattle police officers walk toward a home where Aaron Alexis, the man identified as the shooter in the Washington Navy Yard shootings, has a connection with on Monday, Sept 16, 2013, in Seattle. US authorities probing the shooting spree at Washingto
Seattle police officers walk toward a home where Aaron Alexis, the man identified as the shooter in the Washington Navy Yard shootings, has a connection with on Monday, Sept 16, 2013, in Seattle. US authorities probing the shooting spree at Washington's Navy Yard, which left 13 people dead and eight injured, said Monday that one man only carried out the killings. -- PHOTO: AP

WASHINGTON (AFP) - US authorities probing the shooting spree at Washington's Navy Yard, which left 13 people dead and eight injured, said Monday that one man only carried out the killings.

"We don't have any evidence or indication at this stage that there was another shooter, even though we haven't completely ruled that out," said Washington mayor Vincent Gray.

Police chief Cathy Lanier stressed that: "We do now feel comfortable that we have the single and sole person responsible for the loss of life inside of the base today.

"If anything changes as we continue to go forward, we certainly will make that available to the public," she told a briefing, "but... again, we are lifting the shelter in place warning."

Police have identified the alleged lone gunman as Aaron Alexis of Forth Worth, Texas, who served in the Navy from 2007 to 2011 before becoming a defence subcontractor for computer giant Hewlett-Packard. He was killed in an exchange of gunfire with police.