According to the Daily News, the teen, accompanied by his father [updated: story changed to sister], turned himself in at the 9th Precinct on Fifth Street.
Police say that the teen, who was with two friends, walked up to Williams and allegedly shot him four times in the chest on A between 12th Street and 13th Street. Williams, a 26-year-old father of two, died later at Mount Sinai Beth Israel.
Police have not released a motive in the shooting, though sources have said it was likely gang-related.
Photo from Oct. 11 by Michael Paul