CARY, N.C. — Before a big match, the scene outside a Carolina RailHawks game is hardly unusual for a soccer team in second-to-last place in a second-tier professional league. At the entrance gate, interns at a folding table distribute discounted tickets bought online.

Inside the stadium, however, the mood is different. Protest banners rise from the stands, one quoting language from a federal indictment. The RailHawks, who compete in the North American Soccer League, have a loyal and vocal fan base, and those fans are not pleased that the team has found itself touched by a major international case of sports corruption.

Since May, when the United States Department of Justice announced organized-crime charges against global soccer officials, business executives and two corporations, RailHawks fans have faced an unlikely crisis. Their team, in this Raleigh suburb of about 150,000 people, is owned by a Miami marketing firm that, as one of the two corporations charged, figures prominently in the federal case.

The firm, Traffic Sports USA, and its Brazilian parent company pleaded guilty in May to wire-fraud conspiracy in United States District Court in Brooklyn; sentencing in the case is set for September.