(CBS)“Empire” actor Jussie Smollett, upset after a racist letter sent to the show’s studio didn’t get a “bigger reaction,” is suspected of paying two men to attack him a week later, according to multiple sources with direct knowledge of the investigation.

“When the letter didn’t get enough attention, he concocted the staged attack,” a source told CBS 2 Investigator Brad Edwards. Other sources corroborated that information.

TIMELINE:  Key Developments In The Jussie Smollett Case 

FULL COVERAGE: Read CBS 2’s Coverage Of The Case

The blockbuster revelation into at least part of Smollett’s potential motive comes two days after CBS 2’s Charlie De Mar reported Smollett and two brothers — Ola and Abel Osundairo — staged the attack on Jan. 29 in Streeterville.

De Mar spoke on the phone exclusively with the Osundairo brothers Monday afternoon. In a joint statement, they said: “We are not racist. We are not homophobic, and we are not anti-Trump. We were born and raised in Chicago and are American citizens.”

Smollett received a letter containing a white powder Jan. 22. The letter was mailed to Chicago’s Cinespace Studios, where the show “Empire” is filmed. The letter prompted a HAZMAT response. CPD says the “white substance” was later determined to be aspirin.

The note was crafted with letters apparently cut out from magazines to form words. The pieced-together message contained racial and homophobic threats directed at Smollett. A magazine is one of the pieces of evidence retrieved from the brother’s home last week during a search conducted by CPD. Investigators also recovered a book of stamps.

The brothers are acquaintances of Smollett.

When asked about the letter in a televised interview last week, Smollett said, “On the letter, it had a stick figure hanging from a tree with a gun pointing toward it.” It also had “MAGA” — reference to President Donald Trump’s campaign slogan Make America Great Again – written as the return address.

“In due course all the facts will reveal themselves and at the end of the day my clients are honest and credible” the brothers’ attorney Gloria Schmidt said.

During the search of the brothers’ home last week, a “piece of paper/writing” was also seized. CBS 2 is the only news source with video from inside that house. Police evidence logs exclusively obtained by CBS 2, show investigators took the writing sample, magazine, and a “wallet with stamps.”

Chicago police say the FBI is handling the investigation surrounding the letter, because that’s a federal-level concern.

Smollett claims two men attacked him in Streeterville early Jan. 29 as he was heading to his apartment. He said they yelled racial and homophobic slurs at him, poured a chemical on him and put a rope around his neck.

Sources say at least one of the brothers bought the rope used in the incident at Smollett’s request. The sources also say the “Empire” actor paid for the rope, which was purchased at the Crafty Beaver Hardware Store in the Ravenswood neighborhood the weekend of Jan. 25.

Sources said one of the brothers held the rope and poured bleach while the other wore a plain red hat and yelled slurs at Smollett.

The sources say the red hat was bought at an Uptown beauty supply store and that the attack was supposed to happen before Jan. 29. The brothers told detectives the three men rehearsed the attack days prior to it happening. Smollett paid the brothers $3,500.

When Edwards reached out to CPD, immediately prior to this reporting, a spokesperson responded via text:

“We are not doing any interviews or making any official statements until we can corroborate some information that was shared with police. Until we meet with the Empire cast member, we are not able to confirm, deny or comment on any of the information that was released unofficially.

“When this investigation is over, we will have a detailed accounting of the case. While we are not in a position to confirm, deny or comment on the validity of what’s been unofficially released, there are some developments in this investigation and detectives have some follow-ups to complete which include additional investigation and speaking to the individual who reported the incident.”