From Chicago Police: Photos of people of interest who were in area of the alleged assault & battery of Empire cast member. While video does not capture an encounter, detectives are taking this development seriously & wish to question individuals as more cameras are being reviewed
From Chicago Police: Photos of people of interest who were in area of the alleged assault & battery of Empire cast member. While video does not capture an encounter, detectives are taking this development seriously & wish to question individuals as more cameras are being reviewed
PHOTO: Chicago Police
Now playing
01:56
Police release photo of persons of interest in actor's attack
Now playing
01:33
Chuck Schumer announces timeline for Trump impeachment
Registered nurse Irene Musni administers the COVID-19 vaccine into the arm of a senior citizen at the Corona High School gymnasium in the Riverside County city of Corona, California on January 15, 2021, a day after California began offering the coronavirus vaccine to residents 65 and older. - US President-elect Joe Biden was set to announce his Covid-19 vaccine rollout plan Friday as he bids to wrest the focus from the impeachment of Donald Trump to the agenda for his first days in office.
Biden has said he wants 100 million Americans to receive shots during his first 100 days in office, an ambitious goal that would require a big step up in the current pace of distribution. (Photo by Frederic J. BROWN / AFP) (Photo by FREDERIC J. BROWN/AFP via Getty Images)
Registered nurse Irene Musni administers the COVID-19 vaccine into the arm of a senior citizen at the Corona High School gymnasium in the Riverside County city of Corona, California on January 15, 2021, a day after California began offering the coronavirus vaccine to residents 65 and older. - US President-elect Joe Biden was set to announce his Covid-19 vaccine rollout plan Friday as he bids to wrest the focus from the impeachment of Donald Trump to the agenda for his first days in office. Biden has said he wants 100 million Americans to receive shots during his first 100 days in office, an ambitious goal that would require a big step up in the current pace of distribution. (Photo by Frederic J. BROWN / AFP) (Photo by FREDERIC J. BROWN/AFP via Getty Images)
PHOTO: Frederic J. Brown/AFP/Getty Images
Now playing
01:55
Race to vaccinate before more contagious Covid-19 strains spread
WASHINGTON, DC - JANUARY 22: U.S. President Joe Biden signs an executive order as Vice President Kamala Harris looks on during an event on economic crisis in the State Dining Room of the White House January 22, 2021 in Washington, DC. President Biden spoke on his administration
WASHINGTON, DC - JANUARY 22: U.S. President Joe Biden signs an executive order as Vice President Kamala Harris looks on during an event on economic crisis in the State Dining Room of the White House January 22, 2021 in Washington, DC. President Biden spoke on his administration's response to the economic crisis that caused by the COVID-19 pandemic and signed two executive orders. (Photo by Alex Wong/Getty Images)
PHOTO: Alex Wong/Getty Images North America/Getty Images
Now playing
02:31
Biden zeroes in on the teetering economy in first week
A group of protesters shield themselves from chemical irritants as they demonstrate Wednesday evening, Jan. 20, 2021, outside the U.S. Immigrations and Customs Enforcement (ICE) building in Portland, Ore. (Assfault Pirates via AP)
A group of protesters shield themselves from chemical irritants as they demonstrate Wednesday evening, Jan. 20, 2021, outside the U.S. Immigrations and Customs Enforcement (ICE) building in Portland, Ore. (Assfault Pirates via AP)
PHOTO: Paul L/AP
Now playing
04:04
Portland protesters explain why they are taking to the streets
Hank Aaron, Milwaukee Braves
Hank Aaron, Milwaukee Braves' outfielder, is shown in a posed batting portrait at the Polo Grounds, Brooklyn, during the exhibition season, 1954. (AP Photo)
PHOTO: AP
Now playing
02:30
Hank Aaron, baseball legend and former home run king, dies at 86
PHOTO: CNN
Now playing
01:23
Schumer says articles of impeachment will be delivered Monday
US President Joe Biden listens to the US National Anthem during the virtual Presidential Inaugural Prayer Service hosted by the Washington National Cathedral, in the State Dining Room of the White House in Washington, DC, on January 21, 2021. (Photo by MANDEL NGAN / AFP) (Photo by MANDEL NGAN/AFP via Getty Images)
US President Joe Biden listens to the US National Anthem during the virtual Presidential Inaugural Prayer Service hosted by the Washington National Cathedral, in the State Dining Room of the White House in Washington, DC, on January 21, 2021. (Photo by MANDEL NGAN / AFP) (Photo by MANDEL NGAN/AFP via Getty Images)
PHOTO: Mandel Ngan/AFP/Getty Images
Now playing
03:02
Biden unveils Covid-19 plan on first full day in office
Now playing
00:00
Dr. Fauci vows to be 'completely transparent' on Covid-19
Iraqi security forces keep guard the site of a suicide attack in Baghdad, Iraq January 21, 2021. REUTERS/Thaier al-Sudani
Iraqi security forces keep guard the site of a suicide attack in Baghdad, Iraq January 21, 2021. REUTERS/Thaier al-Sudani
PHOTO: Thaier al-Sudani/Reuters
Now playing
02:42
Dozens killed and hundreds injured in Baghdad suicide blasts
PHOTO: CNN
Now playing
05:46
Dr. Gupta on Covid-19: This is the worst it's ever been
Now playing
03:04
Avlon: QAnon supporters left desperate and disillusioned
Now playing
03:17
Many believed conspiracy theories about Trump and the election. Now, they're losing faith
PHOTO: Courtesy Owen Harrington
Now playing
04:22
He bonded with Biden over stutter. Then got call to speak at inauguration
US President Joe Biden swears in presidential appointees during a virtual ceremony in the Oval Office of the White House in Washington, DC, after being sworn in at the US Capitol on January 20, 2021. (Photo by JIM WATSON / AFP) (Photo by JIM WATSON/AFP via Getty Images)
US President Joe Biden swears in presidential appointees during a virtual ceremony in the Oval Office of the White House in Washington, DC, after being sworn in at the US Capitol on January 20, 2021. (Photo by JIM WATSON / AFP) (Photo by JIM WATSON/AFP via Getty Images)
PHOTO: JIM WATSON/AFP via Getty Images
Now playing
01:29
'I'll fire you on the spot': Biden tells staff to treat others with respect
President Joe Biden signs his first executive order in the Oval Office of the White House on Wednesday, Jan. 20, 2021, in Washington. (AP Photo/Evan Vucci)
President Joe Biden signs his first executive order in the Oval Office of the White House on Wednesday, Jan. 20, 2021, in Washington. (AP Photo/Evan Vucci)
PHOTO: Evan Vucci/AP
Now playing
02:56
Biden signs executive actions aimed at dismantling Trump's policies
Harris
Harris
PHOTO: Senate Tv
Now playing
02:01
A proud Harris smiles as she swears in new senators in her new role

Editor’s Note: This is a developing story and will be updated. You can follow live updates here.

(CNN) —  

A letter containing a white powder was sent to the Chicago set of “Empire” days before one of the show’s stars, Jussie Smollett, was allegedly attacked by two men on January 29.

Chicago police spokesman Anthony Guglielmi told CNN that the letter, received on January 22 at Cinespace Studios, where the show is filmed, prompted a response from the HAZMAT unit.

Guglielmi said authorities determined the powder to be aspirin, but declined to give details on the content of the letter.

The FBI is leading the investigation into the letter, he added.

A spokesperson for 20th Century Fox Entertainment, which produces the series, declined to comment when reached by CNN.

More details

Chicago police continue their investigation into the alleged attack.

Smollett said his attackers physically assaulted him and called him homophobic and racist slurs, according to police.

Smollett, who was returning from an early morning trip to a Subway sandwich shop, also reported that one of his attackers put a rope around his neck and poured an unknown substance on him, police said.

Investigators have video of Smollett entering the hotel after the alleged attack with what appears to be a noose around his neck, Guglielmi said.

Police are in possession of the rope and the sweater Smollett was wearing on the night of the attack and are testing the substance, according to Guglielmi.

Smollett and his manager, Brandon Moore, told authorities they were speaking on the phone with each other at the time of the attack, police said.

Guglielmi said because of the financial relationship between the two men, they are trying to verify the call took place and have requested phone records or the physical phones used for the call.

Police were called 30-40 minutes after the attack took place, Guglielmi said.

Detectives have collected and are reviewing more surveillance video from neighboring hotels and apartments, but have not found video of the incident at this point, Guglielmi said.

On Wednesday, police released photos of two individuals who are now wanted for questioning in connection with the case.

Smollett has starred on Fox’s “Empire” since 2015. He plays Jamal, a successful singer in the musical Lyon family. Like his character, Smollett identifies as gay.

Family responds

On Thursday, the Smollett family condemned the “violent and unprovoked attack,” calling it “a racial and homophobic hate crime” in their first official statement since the incident.

“Jussie has told the police everything from the very beginning,” the statement said. “His story has never changed, and we are hopeful they will find these men and bring them to justice.”

In the aftermath of Smollett’s assault, his friends, colleagues and peers showed an outpouring of support for the actor, who is an active advocate for the LGBTQ community.

“Our family thanks everyone for their prayers and the huge amount of love he has received. We are thankful to our village for your immense support during this trying time,” the statement added. “We are so grateful that God saw him through this cowardly attack alive. Jussie is a warrior whose light cannot be dimmed.”