Chicago's disgraced police department is facing a federal civil rights investigation after cops were caught appearing to 'delete' footage of teen Laquan McDonald being shot 16 times by a white police officer.

Illinois Attorney General Lisa Madigan has asked the U.S. Department of Justice to investigate whether the department's practices violate federal and constitutional law.

This week Chicago Mayor Rahm Emanuel ousted the city's police chief after a public outcry over the handling of the case, but now footage has emerged on social media in which a Chicago police officer accuses Emanuel of colluding in a cover-up.

Chicago's disgraced police department is facing a federal civil rights investigation after cops were caught appearing to 'deleting' footage of Laquan McDonald's shooting as one police officer (pictured) accused Chicago Mayor Rahm Emanuel of colluding in the cover-up

A short clip emerged on social in which an officer states that Emanuel 'paid the family to shut them up'

Mayor Rahm Emanuel (pictured) announced on Tuesday the dismissal of Police Superintendent Garry McCarthy in response to protests sparked by the shooting death of Laquan McDonald

The 15-second clip, filmed at a rally, was posted originally on Instagram by @xaneetta then shared on Twitter by an account belonging to radio host Yesenia Alvarez.

It shows an officer state that Emanuel 'paid the family to shut them up.'

Emanuel announced at a news conference on Tuesday morning that he had dismissed Superintendent Garry McCarthy, who only days ago insisted to reporters that the mayor had his 'back.'

Protesters had been calling for McCarthy's dismissal for days. He has been at the helm of the Chicago PD since May 2011.

Laquan McDonald's family spoke out in praise of Emanuel's decision, but said they were shocked by the news that there had been a $5 million settlement with the city after Laquan's death - they said it was negotiated by his great uncle.

'No one in my family would settle for this. And if it was the case of this happening, I don't know about it, and I was his caregiver,' uncle Shyrell Johnson told FOX 32 Chicago.

At the weekend never-before-seen screengrabs emerged from inside a Chicago Burger King showing what appears to be police officers at a computer terminal on the night of October 20, 2014, when McDonald was gunned down.

Rev. Al Sharpton comforts Cleo Pendleton, below, whose 15-year-old daughter, Hadiya Pendleton, was killed in Chicago in 2013, as Spike Lee, second from left, and Nick Cannon, left, listen to her speak

Demonstrators pose for a picture in front of the City of Chicago Public Safety Headquarters during a protest over the killing of Laquan McDonald on December 1 in Chicago

Police stand guard in front of the City of Chicago Public Safety Headquarters during a protest over the killing of Laquan McDonald on Tuesday evening. The building houses the Chicago police headquarters

On Tuesday, Madigan said the death of McDonald, raises serious questions about the use of lawful and excessive force.

She says trust in the police department is 'broken'.

In a letter to U.S. Attorney General Loretta Lynch, Madigan noted four other high-profile cases in Chicago, including the death of Ronald Johnson, 25,who was shot by police last year.

'The shocking death of Laquan McDonald is the latest tragedy in our city that highlights serious questions about the use of unlawful and excessive force by Chicago police officers and the lack of accountability for such abuse,' Madigan said.

Police Superintendent Garry McCarthy (right) had only days ago insisted to reporters that the mayor (left) had his 'back'

In this grainy screengrab obtained exclusively by NBC 5 , at least one officer is seen sitting at a computer in the back office of a Chicago Burger King on the night of October 20, 2014, when McDonald was gunned down

'Trust in the Chicago Police Department is broken. Chicago cannot move ahead and rebuild trust between the police and the community without an outside, independent investigation into its police department to improve policing practices.

'I know the vast majority of officers in the Chicago Police Department serve with bravery, honor and integrity.

The now-outgoing Police Superintendent McCarthy said there appeared to have been technical difficulties with surveillance video from the Burger King on Pulaski road after the shooting

'The children in all of Chicago's communities deserve to grow up in a city in which they are protected and served by the police.'

Madigan says an investigation by the U.S. Justice Department's civil rights division is 'necessary and appropriate' because of its experiences looking into police department practices nationwide.

She says the handling of investigations of police misconduct by an independent panel, police board and superintendent also raises troubling questions.

Other Cook County and Chicago leaders have backed her viewpoint, saying they're not satisfied with Emanuel dismissing McCarthy.

Cook County Commissioner Richard Boykin said a federal investigation is needed and the firing is a 'necessary but insufficient first step.' Alderman Carlos Ramirez-Rosa also called for an independent investigation.

On Tuesday night, at the New York premiere of his movie 'Chi-Raq', criticized the mayor and predicted that 'some more heads are gonna roll'.

The police superintendent 'is not going to be the only one,' Lee said.

Lee spoke before he and cast members participated in an anti-gun violence march.

Chicago actor John Cusack, who appears in the film, said the shootings and killings in Chicago each year are 'unacceptable' and cited political motives.

He said the police officer involved in shooting McDonald wasn't charged or the superintendent fired until the city's election had passed. Emanuel won a second term earlier this year. The shooting took place in 2014.

Chicago police Officer Jason Van Dyke (left) was charged on Tuesday with first degree murder in the killing of 17-year-old Laquan McDonald on October 20, 2014 (right)

Lee's satire is based on the ancient Greek play 'Lysistrata' by Aristophanes. His modern adaptation is about the murder of a child hit by a stray bullet in Chicago's South Side, and the group of women that organize a unique way of dealing with the ongoing violence - they hold back sex.

The Rev. Al Sharpton, who walked the film's orange carpet before the premiere, said the power of the satire can send a message to young people about gun violence more than Tuesday's announcement in Chicago.

Cook County State's Attorney Anita Alvarez has denied a cover-up, stating during a press conference last week that forensic testing showed the Burger King's computer files had not been tampered with.

The manager of the fast-food restaurant on Pulaski Road has repeatedly claimed that Chicago police deleted 86 minutes of footage recorded by outside surveillance cameras in the aftermath of the teenager's deadly shooting at the hands of white officer Jason Van Dyke.

A district manager at a Chicago Burger King (pictured) claims police wiped more than an hour of surveillance footage from the chain's servers after last year's shooting of Laquan McDonald

Van Dyke, 37, was released from jail on Monday after posting bond on $1.5million bail.

In grainy images obtained exclusively by NBC 5, at least one officer is seen at a computer in the back office of the Burger King on Pulaski Road.

McCarthy said there appeared to have been technical difficulties with the surveillance video, but there was no evidence of tampering.

During Tuesday's press conference, Mayor Emanuel praised McCarthy's leadership of the force but called it an 'undeniable fact' that the public's trust in the police had eroded.

'Now is the time for fresh eyes and new leadership,' Emanuel said. 'Any case of excessive force or abuse of authority undermines the entire force and the trust we must build with every community in the city.'

Police dashcam footage released this week showed the moment Van Dyke, circled, pointed his weapon at Laquan McDonald, right, additional evidence may have been caught on surveillance at Burger King

Moments later, McDonald, circled, was lying mortally wounded on the floor as Van Dyke shot up up to 16 times with his service weapon

Chief of Detectives John Escalante will oversee the police department until a permanent replacement is named.

The mayor said he wants the next chief to safeguard public safety and restore trust between the community and the police.

The mayor also announced the creation of the Task Force on Police Accountability, which will be advised by former Massachusetts Governor and Chicago native Deval Patrick.

It will include former director of the Illinois State Police, Hiram Grau and Chicago Police Board president Lori Lightfoot.

The mayor told reporters McDonald's death 'requires more than just words.'

Among the five-person panel's responsibilities will be to improve oversight of police misconduct, find the best ways to identify and evaluate officers with repeated complaints and recommend how to release videos of police-involved incidents.

Demonstrators protest outside the office of Mayor Rahm Emanuel at City Hall following press conference where the mayor announced the firing of Chicago Police Superintendent Garry McCarthy on December 1