CHICAGO (AFP/REUTERS) - Racial tensions soared in two US cities on Tuesday (Nov 24) after gunmen opened fire on a Black Lives Matter protest in Minneapolis and a Chicago police officer was charged with murder for shooting a black teen.
A 23-year-old white man was arrested before midday in the Minneapolis suburb of Bloomington and two men aged 26 and 21, both white, turned themselves in and were later arrested, police said.
A fourth man, whom police arrested near midday, was released after investigators determined he had not been at the scene of the shooting, which happened late on Monday about a block from the protest over the shooting of Jamar Clark, the police said.
The younger suspect was arrested around 11.20am local time in the Minneapolis suburb of Bloomington, while the older man was arrested in his vehicle about 45 minutes later in south Minneapolis, the police said.
"As I said before, we are sparing no efforts to bring any and all those responsible to justice," Minneapolis Mayor Betsy Hodges said after the second arrest. In an earlier statement, she said she abhorred the attack on the demonstrators.
The authorities said they will release the suspects' names after charges are filed and the search for additional suspects continues. Police declined to say whether they were looking for one or more additional suspects.
A spokesman said the Hennepin County Attorney's Office was aware of the arrests and was waiting for a case to be presented for consideration.
Five people were wounded, though none gravely, when the gunmen opened fire on Monday night at the Minneapolis protest, police said.
Black Lives Matter Minneapolis vowed to continue its daily demonstrations protesting the fatal police shooting of Jamar Clark, 24, whom they said was handcuffed when he was shot in the head on November 15.
"White supremacists attacked the #4thPrecinctShutDown in an act of domestic terrorism," the group wrote on its Facebook page. "We won't be intimidated."
Meanwhile, the mayor of Chicago called for calm ahead of the release of a "hideous" video showing officer Jason Van Dyke fire 16 bullets into Laquan McDonald, 17.
A judge ordered the Chicago police dashcam video released to the public no later than Wednesday.
Van Dyke was charged with first degree murder Tuesday, the Chicago Tribune reported.
It will be the first time a Chicago police officer has been charged with first-degree murder for an on-duty fatality in more than 30 years, the newspaper said.
"We trust police officers to provide safety, build trust and uphold the law. If you violate that you're going to be held accountable," Mayor Rahm Emanuel told reporters Monday.
"This is a violation of your conscience and it is wrong and it is hideous."
Emanuel spoke with community leaders and urged them to remind residents to express their right to protest in a "responsible, focused, peaceful way so your voices and your ideas are heard."
The city approved a US$5 million (S$7.08 million) settlement for McDonald's family in April and federal authorities have said they are investigating the case.
His family has said they do not want the video released because it will be too painful to see it played over and over again on the news.
"My nephew is shot in the back and all of those other places 16 times. Even when he was on the ground, the officer was still shooting him," McDonald's uncle, Shyrell Johnson, told WGN-TV last week.
Police have said McDonald was high on PCP, acting erratically and lunged at the officers with a knife.
"Despite the graphic nature of the video, we're confident that my client's actions were not only lawful, but also within department policy and within his training," Van Dyke's attorney, Daniel Herbert, told reporters last week.
"He was in fear for his life." Van Dyke, who has been on desk duty since the October 2014 shooting, did not speak to reporters when he arrived at the Chicago courthouse Tuesday morning.
In Minneapolis, police have said Clark died in a struggle with police who were responding to a domestic disturbance.
His brother on Tuesday thanked demonstrators for their continued vigilance but asked them to halt activity out of concern, according to the Minneapolis Star Tribune.
"Thank you to the community for the incredible support you have shown for our family in this difficult time," his brother Eddie Sutton said in a statement, according to the paper.
"In light of tonight's shootings, the family feels out of imminent concern for the safety of the occupiers, we must get the occupation of the Fourth Precinct ended and onto the next step."
Minneapolis police said they were "actively investigating the shootings" and that additional uniformed officers had been called to the area.