"Due to new evidence as a result of today's interrogations, the individuals questioned by police in the Empire case have now been released without charging and detectives have additional investigative work to complete," the Chicago Police Department said in a email to Reuters.
The individuals are no longer being classified as suspects, the department said.
A spokesman for the department on Friday night declined to confirm to Reuters whether the individuals released were the two Nigerian brothers police said they arrested on Wednesday at Chicago O'Hare Airport in connection to the attack.
Authorities had previously said only that the pair, whose names have not been released, were persons of interest after they were recognized from surveillance camera footage taken in the area where Smollett said two men shouted slurs at him and put a rope around his neck on Jan. 29.