The men arrested were the same men who according to police were considered "potential suspects," according to Tom Ahern, deputy director of Chicago police communications.
The men, who according to police were arrested on Wednesday, were not charged.
At the beginning of Friday, police spokesman Anthony Guglielmi said that two Nigerian brothers were being treated as "potential suspects" and that the detectives had "probable cause of being involved in an alleged crime".
The police did not say at that time exactly what the two brothers were accused or what the alleged crime might have been.
Smollett, one of the stars of "Empire", told the authorities that he was attacked at the beginning of January 29 by two men who launched "racist and homophobic insults" against him.
After a short battle, both men fled, and Smollett told the police that an attacker had supposedly put a rope around his neck and poured him an unknown chemical.
"The interrogations will resume today with the two individuals and their lawyer," Guglielmi said in his statement on Friday. "Even if we have not found any video that documents the alleged attack, there is no evidence to say that it is a hoax."
"The alleged victim is cooperating right now and continues to be considered a victim, not a suspect," he added.
Police said Thursday they were interrogating the two men after meeting them at Chicago O'Hare International Airport on Wednesday night, but they were not considered suspect at the time. Their apartment was raided by the police at the start of this week.
One of the brothers appeared in the "Empire" show, according to the police.
The authorities have previously released surveillance images of two figures projected in the area of the attack, which they thought were wanted to be interrogated.
"I never said that," he said. "I did not need to add anything like that, they called me af **** t, they called me a ***** There's no way I cut it, I do not need a MAGA hat like [1
CNN Brad Parks contributed to this report.