Arlington Heights police officers assigned to Recreation Park for Frontier Days responded about 10:10 p.m. Sunday to a report of a fight in progress near the west side of the park. Police received a report of about 50 youths fighting, who stopped fighting and had moved near the swings on the west side of the park. The situation was under control about 10:15 p.m. Police arrested at least one youth for violation of village ordinance. The youth was transported to Arlington Heights police headquarters in custody.