Chicago Mayor asked for resignation of Chicago Police Superintendent

(CNN) -- Chicago Mayor Rahm Emanuel said Tuesday that he has asked for the resignation of Chicago Police Superintendent Garry McCarthy.

Amid angry protests in Chicago over the way the city responded to the killing by police of a black teenager, Mayor Rahm Emanuel is set to announce Tuesday a new task force on law enforcement accountability.

The task force, his office said in a statement, will review how the city trains and oversees its police officers. The group will consider input from victims' rights representatives, law enforcement organizations, and youth and religious leaders.

The protests in Chicago echo a national campaign led by Black Lives Matter activists. That campaign claims police across the country discriminate against black people. They point to cases in New York; Ferguson, Missouri; Baltimore and other cities, where they say cops use excessive -- sometimes deadly -- force against black males.

In Chicago, the outrage has been focused squarely on the killing of Laquan McDonald in October 2014. Dashboard camera footage recorded the teen, who was carrying a 4-inch knife, walking yards away and turning his back to Officer Jason Van Dyke when Van Dyke opens fire, shooting the teen 16 times.

A freelance journalist filed suit, arguing that the video was public record. The city went to court to prevent its release. A judge sided with the journalist, and the footage was released last week.

Protesters took to Chicago's streets, including prominent African-American leaders such as U.S. Rep. Bobby Rush, D-Illinois. They rallied day after day, peacefully interrupting holiday shopping over the Thanksgiving weekend.

"Stop the cover-up!" they shouted, and "16 shots! 16 shots!"

Protesters have repeatedly demanded that Emanuel resign, the chief of police be fired and a federal investigation examine the behavior of public officials involved in the case.

A rally is planned for Tuesday afternoon.

Also, CNN has learned that at 11:30 a.m. ET, a mother who says police shot her young son will demand that the dashboard camera footage in that case be released.

At noon, Emanuel is expected to address media.

Officer out of jail, new suspect in

When the video was released last week, Van Dyke was charged with first-degree murder.

He walked out of jail on bond Monday evening after a judge set his bail at $1.5 million.

Van Dyke had a history of complaints before he gunned down McDonald, and in almost every case, he was cleared in one way or another. The allegations mostly involve excessive force, and at least one complaint alleges that he used a racial slur.

There appear to be no criminal proceedings against Van Dyke before last week, but a jury did award a Chicago man $350,000 after determining that Van Dyke used excessive force during a traffic stop. (The city of Chicago also gave McDonald's mother, who had not yet filed a lawsuit, $5 million in April.)

Meanwhile, a scary moment occurred Monday when a man allegedly threatened to shoot white men to avenge McDonald's death. Jabari Dean, 21, was arrested and accused of threatening to kill students and staff at the University of Chicago.

According to a criminal complaint, Dean posted a threat on social media this past weekend.

"This is my only warning. At 10 a.m. on Monday mourning (sic) I am going to the campus quad of the University of Chicago. I will be armed with a M-4 Carbine and 2 Desert Eagles all fully loaded. I will execute aproximately (sic) 16 white male students and or staff, which is the same number of time (sic) Mcdonald (sic) was killed," the post read.

"I then will die killing any number of white policemen that I can in the process. This is not a joke. I am to do my part to rid the world of the white devils. I expect you to do the same."

Dean is charged with transmitting a threat in interstate commerce. He is facing up to five years in prison.

CNN's Michael Pearson, Dani Stewart and Dana Ford contributed to this report.