US navy yard shooting: District of Columbia Mayor Vincent Gray gives press conference after suspect Aaron Alexis is captured

In this footage, District of Columbia Mayor Vincent Gray and Washington Police Chief Cathy Lanier can be seen giving updates on the US Navy Yard shooting yesterday.

Mr Gray tells the press gathered that "we obviously have had a horrific tragedy this morning" in response to the shootings at the US navy yard on Monday, that saw 12 dead and four others, including one policeman seriously injured.

Cathy Lanier, Columbia Police Chief tells the press that they had captured one shooter and explains there are "multiple victims inside that are deceased". Ms Lanier also tells the press police are concerned there may be two other shooters involved.

Washington law enforcement officials have since confirmed they believe 34-year-old suspect Aaron Alexis was the "single and sole person" who opened fire. Alexis, a former navy reservist, was shot and fatally wounded inside the building by police.