(CNN) -- Two law enforcement sources with knowledge of the investigation tell CNN that Chicago Police believe actor Jussie Smollet paid two men to orchestrate an assault on him that he reported late last month.
The men, who are brothers, were arrested Wednesday but released without charges Friday after Chicago police cited the discovery of "new evidence."
The sources told CNN the two men are now cooperating fully with law enforcement.
Smollett told authorities he was attacked early January 29 by two men who were "yelling out racial and homophobic slurs." He said one attacker put a rope around his neck and poured an unknown chemical substance on him.
The sources told CNN there are records that show the two brothers purchased the rope found around Smollett's neck at a hardware store in Chicago.
CNN's attempts Saturday to reach both Smollett's representative and attorney were unsuccessful.
Smollett identifies as gay and since 2015 has played the gay character of Jamal on the Fox TV drama "Empire."
According to Chicago Police spokesman Anthony Guglielmi, the actor told detectives he was attacked by two men near the lower entrance of a Loews hotel in Chicago. Police were told the two men yelled "'Empire' fa***t" and "'Empire' n***er'" while striking him.
The day after the incident, police released surveillance images that showed two silhouetted individuals walking down a sidewalk, and police said they were wanted for questioning.
The two men were arrested Wednesday. Police on Friday said the men were being viewed as "potential suspects" and that detectives had "probable cause that they may have been involved in an alleged crime."
But by Friday night they had been released, Guglielmi said, "due to new evidence as a result of today's investigations."
"And detectives have additional investigative work to complete," he added.
One of the men has appeared on "Empire," Guglielmi said. A police source also told CNN on Friday night that the men had a previous affiliation with Smollett, but did not provide additional details.
Smollett has expressed frustration about not being believed
Following the alleged attack, Smollett's colleagues and fans rallied around him, expressing shock and sadness.
"We have to love each other regardless of what sexual orientation we are because it shows that we are united on a united front," Lee Daniels, the creator of "Empire," said in a video posted to his Instagram page on January 29. "And no racist f*** can come in and do the things that they did to you. Hold your head up, Jussie. I'm with you."
Smollett gave his first detailed account of what he says was a hate crime against him, and the aftermath, in an interview with ABC's "Good Morning America" that aired Thursday.
During the interview he expressed frustration at not being believed.
"It feels like if I had said it was a Muslim or a Mexican or someone black I feel like the doubters would have supported me a lot much more," Smollett said. "And that says a lot about the place where we are as a country right now."
Smollett also refuted reports that said he told police the attackers wore "Make America Great Again" hats.
"I never said that," he told ABC's Robin Roberts. "I didn't need to add anything like that. They called me a f****t, they called me a n****r. There's no which way you cut it. I don't need some MAGA hat as the cherry on some racist sundae."