4 other people involved in fight taken into custody, officials say2 off-duty police officers among 4 victims injured in fight at 31st Street Beach, Chicago police sayTwo off-duty police officers were among four victims injured in a fight Friday at 31st Street Beach on the South Side, Chicago police said. Two off-duty police officers were among four victims injured in a fight Friday at 31st Street Beach on the South Side, Chicago police said. Two off-duty police officers were among four victims injured in a fight Friday at 31st Street Beach on the South Side, Chicago police said. Two off-duty police officers were among four victims injured in a fight Friday at 31st Street Beach on the South Side, Chicago police said. CHICAGO (WLS) -- Two off-duty police officers were among four victims injured in a fight Friday afternoon at a beach on the city's South Side.