On Friday, Chicago police referred to them as “potential suspects,” but by Friday evening, they had been released without being charged. The police still have not publicly said why.

The brothers, Olabinjo Osundairo and Abimbola Osundairo, could not be reached for comment. Ms. Schmidt declined to comment Saturday on the reports but said the brothers had completed their cooperation with the police.

Smollett has rejected skepticism about his account that emerged on social media after he made his initial report to law enforcement.

In that account, Smollett, who is black and gay, said that in the early morning hours of Jan. 29, he was attacked by two masked men who made a reference to “Empire.” He also said that the attackers made a reference to “MAGA country,” an allusion to President Trump’s campaign slogan, “Make America Great Again.” According to Smollett’s account, the men then tied a noose around his neck, poured a chemical substance on him and fled.

Investigators could not generate many leads on finding suspects. There was no surveillance footage of the attack in an area of the city that the police said was heavily covered with cameras. Days after Smollett first spoke to the police, the department released an image showing two men that they said were potential persons of interest; according to the police, those ended up being the two men they detained this week. That the men, who are of Nigerian descent, were acquaintances of Smollett, fueled further speculation about the circumstances of an assault.

A spokesman for Fox, the network on which “Empire” airs, declined to comment.

In an interview broadcast Thursday on “Good Morning America,” Smollett was adamant that his story was true. For weeks, law enforcement backed up his assertions, saying publicly that investigators had no reason to doubt his story.