The nightclub catered to a primarily gay clientele.
Fifty-three people were wounded, some of them gravely. Twenty-nine-year-old Omar Saddiqui Mateen - an American born to Afghan parents - opened fire in the Pulse nightclub in downtown Orlando, Florida early Sunday morning. Sunday night for the 50 people shot dead in the worst mass killing in U.S.
Thousands of people, gay and straight, held candlelight vigils in several major cities across the U.S.
