A jury found Illini basketball star Terrence Shannon not guilty of rape. Then the online harassment of his accuser started.

LAWRENCE, Kansas — Less than two hours had passed since the not guilty verdict came down, and their names and photographs were already published and viewed millions of times on social media.

Some said the 19-year-old should be prosecuted for accusing Terrence Shannon Jr. of rape when a Douglas County jury decided no such crime could be proved beyond a reasonable doubt. Others said the Chicago native and University of Illinois men’s basketball star should sue her and her best friend, also 19...