Developments over the weekend "shifted the trajectory" of the investigation into the Jan. 29 attack on "Empire" actor Jussie Smollett.

The actor told police last month he was attacked in Chicago in the early hours of the morning by two masked men who shouted "racial and homophobic slurs." Police said Smollett described the assailants punching him in the face, pouring a chemical on him and wrapping a rope around his neck.

Police are still waiting to hear from the actor regarding a follow-up interview so they can ask him questions relating to the claim of two brothers who say they were paid by the actor to orchestrate the attack.

Here are the most recent developments in the case:

California police: Smollett posed as his brother during suspected DUI stop in 2007

Smollett's credibility came under attack again Tuesday when the Los Angeles City Attorney's Office confirmed an NBC News report that the actor posed as his brother Jake when stopped for a suspected DUI in Los Angeles in July 2007 and signed his brother's name on the summons promising to appear in court.

Frank Mateljan, a public information officer in that office, confirmed to USA TODAY Wednesday that Smollett pleaded no contest to driving under the influence, driving without a license and providing false information to law enforcement in September of that year. He was sentenced to three years' probation plus fines or three days in jail.

USA TODAY has requested comment from Smollett's representatives and his brother.

Chicago prosecutor Kim Foxx recuses herself from Smollett case

Cook County State’s Attorney Kim Foxx announced she was recusing herself from the investigation on Tuesday.

“Out of an abundance of caution, the decision to recuse herself was made to address potential questions of impartiality based upon familiarity with potential witnesses in the case,” Tandra Simonton, a spokeswoman for Foxx, said in a statement.

Simonton declined to comment on which potential witnesses Foxx was referencing.

FBI is looking into whether Smollett had a hand in threatening letter

The FBI is probing whether Smollett had any role in sending a threatening letter that was mailed to the actor at the Chicago studio where "Empire" is filmed a week before the alleged assault, a federal government official who has been briefed on the investigation told USA TODAY.

The official, who was not authorized to comment on the ongoing investigation, said the FBI probe is still in the preliminary stages.

FBI officials declined to comment.

Last week, Chicago police officer Michael Carroll confirmed to USA TODAY that the mail, received Jan. 22, contained a white substance. The powder was later determined to be acetaminophen, or Tylenol.

Smollett said in an interview with “Good Morning America” last week that he believes the letter was linked to the alleged assault on him.

He said the letter “had a stick figure hanging from a tree with a gun pointing towards it with the words that said 'Smollett, Jussie you will die,' " he said, adding that the return address area simply said "MAGA."

Police say a tip Smollett was seen in an elevator with alleged attackers is 'unfounded'

Police investigated a tip that on the night Smollett reported being attacked, he was in an elevator of his apartment building with two brothers who were later arrested and released from custody in the probe.

Department spokesman Anthony Guglielmi tweeted Tuesday night that the tip "is unfounded as it was not supported by video evidence obtained by detectives."

Guglielmi said a person who lives in the building or was visiting someone there reported seeing the three together that night. .

Smollett case could go to a grand jury

Smollett’s case could be headed toward a grand jury soon, a law enforcement official familiar with the investigation told USA TODAY.

The official was not authorized to speak publicly about the ongoing deliberations.

TMZ reported Monday that the case could head to a grand jury next week. But the law enforcement official told USA TODAY that investigators have no firm date for referring the case.

“We’re still hopeful he’ll come in and talk to us,” the official said.

Brothers say Smollett paid them to carry out assault

After being arrested, a pair of Nigerian siblings in their late 20s who reside in Chicago told detectives that they were paid to stage the attack, a person familiar with the investigation but not authorized to speak publicly told USA TODAY.

Police also found records in the Chicago home of one of the men that showed they purchased rope from a hardware store that was used in the alleged attack, the source told USA TODAY.

The brothers were released Friday with police citing new evidence in the case. They were not charged.

Police spokesman Tom Ahernsaid the brothers met with police and prosecutors Tuesday. They did not testify before a grand jury.

Smollett, 36, who is black and gay, said he was attacked while walking home through Chicago’s Streeterville neighborhood. He told police masked men tied a noose around his neck and yelled, "This is MAGA country" before leaving the scene.

Smollett case:Two men released after police interrogation reveals 'new evidence'

Police:Two brothers told investigators they were paid by Jussie Smollett to stageattack

Smollett acknowledges knowing the brothers but denies involvement

In a statement issued late Saturday, the actor's attorneys, Todd Pugh and Victor P. Henderson, confirmed to USA TODAY that the star knew the brothers and employed one as his trainer to get him physically ready for a music video.

Smollett was "angered and devastated by recent reports that the perpetrators are individuals he is familiar with," his attorneys said in a statement.

Pugh and Henderson added, "He has 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."

Detectives want to interview Smollett again

On Sunday, Guglielmi confirmed that detectives had requested a follow-up interview with the actor, tweeting, "There are some developments in this investigation and detectives have some follow-ups to complete which include speaking to the individual who reported the incident."

Pamela Sharp, Smollett’s spokeswoman, issued a statement to USA TODAY Monday from her client's attorneys, Todd S. Pugh and Victor P. Henderson, who said Smollett had no plans to meet with authorities that day.

“There are no plans for Jussie Smollett to meet with Chicago police today," the statement read. "Any news reports suggesting otherwise are inaccurate. Smollett's attorneys will keep an active dialogue going with Chicago police on his behalf. We have no further comment today.”

Fox rejects theory Smollett staged attack to avoid being written off 'Empire'

In a statement issued late Thursday, the network shot down a story by ABC7 Chicago alleging the actor was trying to garner sympathy to convince the network not to write him off the show.

"The idea that Jussie Smollett has been, or would be, written off of 'Empire' is patently ridiculous," the network told USA TODAY Thursday. "He remains a core player on this very successful series and we continue to stand behind him."

Backlash grows

In a lengthy interview with "Good Morning America" host Robin Roberts Thursday, Smollett spoke of his frustration not just with his assailants but those who have attacked him in the press and on social media, saying that they not only "don't believe this is the truth" but "don't even want to see this is the truth."

However, his doubters grew louder over the weekend following the announcement that the police are now actively investigating the hoax angle.

Former Obama strategist David Axelrod summed up the fears of many Sunday when he tweeted, "The racist/homophobic attack @JussieSmollett alleged was horrific. But if this story turns out to be a hoax, orchestrated by Smollett to boost his career, he will have cynically betrayed supporters across the country."

REGARDLESS OF SMOLLETT: Crimes against blacks, gays are up, according to FBI (Jan. 31)

Meanwhile, Donald Trump Jr. went after Smollett, whom he said "tried to manufacture a hate crime" to make his father's supporters look bad and the media who, "not only uncritically accepted his lies as facts for weeks, but attacked those who questioned the validity of his false story." He also took aim at 2020 Democratic contender Sen. Kamala Harris and various "Hollywood and media types," asking if they still wanted "#JusticeforJussie."

Director Ava DuVernay said Sunday that despite any inconsistencies in Smollett's story, she "can't blindly believe the Chicago PD" given its handling of Laquan McDonald's shooting death and its past use of torture.

"He might have lied. He might not have. I don’t know. But what I do know?" the "Wrinkle in Time" director wrote. "I never believe police on general principle just ‘cause they say so. My experience, our history, makes it impossible for me to do so."

Jussie Smollett: 'Empire' producer stands bystar, DuVernay says, 'He might have lied'

Smollett recounts violent attack on 'GMA': I saw the rope 'and I started screaming'

Contributing: Aamer Madhani, Bill Keveney and The Associated Press