CBS News has learned that a last-minute phone call may have saved "Empire" star Jussie Smollett from potentially being indicted. Last month, the actor claimed he was the victim of a racist and homophobic attack as he walked home in the middle of the night. Two brothers have now told Chicago police Smollett paid them to stage the assault.

A source close to the investigation tells CBS News the brothers were set to appear in front of a grand jury Tuesday. But CBS News correspondent Dean Reynolds reports those plans were abruptly scrapped after a "Hail Mary" call from Smollett's defense team.

CBS News has learned that Nigerian brothers Ola and Abel Osundairo were waiting outside the grand jury chambers, just minutes from testifying, when prosecutors got the call from Smollett's lawyers.

It's unclear what the defense said, but the Cook County state's attorney decided to postpone the brothers' testimony, which would have been the first step toward indicting the 36-year-old actor for filing a false police report.

Smollett has repeatedly denied staging the attack.

"I'm pissed off. How do you not believe that?  It's the truth!" he said recently on "Good Morning America."

According to a source close to the investigation, after the brothers told police they conspired with Smollett, his lawyers told police he would not do a follow-up interview.

About a dozen search warrants have now been issued, including ones for Smollett's financial and phone records, and detectives are waiting for those records to come back.

The Osundairos told detectives they conspired with Smollett in the fake January 29 attack.

CBS Chicago reports the brothers now also claim Smollett was behind the threatening letter sent to him a week before the alleged assault.

On Tuesday, Smollett's brother and sister posted Instagram messages appearing to criticize media coverage of the case. "It will make the criminal look like he's the victim and make the victim look like he's the criminal," read a quote attributed to Malcolm X.

Two other siblings defended Smollett last week.

Jake Smollett said, "When one is affected, we are all affected. So it definitely was a time we came together. And we are a strong family."

Smollett has also denied involvement with the threatening letter.

On Tuesday, in response to reports his scenes in "Empire" were being cut, 20th Century Fox and Fox Entertainment said they were standing behind the actor.