Chicago (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."

What happened

According to Chicago Police spokesman Anthony Guglielmi, the actor told detectives he was attacked by two men near the lower entrance of a Lowe's store 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.