Although Chicago Police Superintendent Eddie Johnson delivered a press conference outlining the steps they believe Jussie Smollett took to orchestrate the attack against himself, the FBI revealed it's still working with the US Postal Service to determine whether the Empire actor was behind the threatening letter.

The racist and homophobic letter contained a white power—which was later determined to be aspirin—and was addressed to Smollett at the Chicago's Cinespace Studios where Empire is filmed. Smollett first received the letter on Jan. 22, then the alleged attack occurred a week later.

Two federal officials told ABC News there is an open investigation into whether Smollett was tied to the sending of the letter.

During the press briefing with news outlets, Supt. Johnson claimed that Smollett was responsible for the letter and the attack because he was unhappy with his salary on the show.

Last Wednesday, the Chicago Police Department took Nigerian brothers Olabinjo Osundario and Abimbola Osundairo into custody. Although the Osundario brothers were questioned by police, they were released with no charges.

Police said they found magazines in the home of the brothers, but there has not been an official statement on whether or not the letters came from their magazines.

The Chicago Police Department has been extremely vocal about how they now have reason to believe Smollett paid the brothers to execute the attack. 

On Saturday, Smollett's attorneys Todd S. Pugh and Victor P. Henderson released a statement to CNN in response to reports that the actor staged the attack.

"As a victim of a hate crime who has cooperated with the police investigation, Jussie Smollett is angered and devastated by recent reports that the perpetrators are individuals he is familiar with," the statement to CNN read. "He has now been further victimized by claims attributed to these alleged perpetrators that Jussie played a role in his own attack. Nothing is further from the truth and anyone claiming otherwise is lying."

Most recently, Smollett was reportedly cut from some Empire scenes and may have been suspended from the show indefinitely.