Updated at 11:23 a.m. ET

The Justice Department says it has made the investigation into George Floyd's death "a top priority," after furor over a video depicting a white police officer kneeling on his neck spilled over into widespread protests for a second night.

Demonstrators gathered both in Minneapolis, where the black man died after his arrest, and as far afield as Los Angeles.

"The federal investigation will determine whether the actions by the involved former Minneapolis Police Department officers violated federal law," U.S. Attorney for the District of Minnesota Erica MacDonald and Rainer Drolshagen, the FBI Special Agent In Charge of the Minneapolis field office, said in a joint statementThursday. "It is a violation of federal law for an individual acting under color of law to willfully deprive another person of any right protected by the Constitution or laws of the United States."

They said the "robust criminal investigation" is being spearheaded by the department's Civil Rights Division and the local FBI field office.

"Upon conclusion of the FBI's investigation," they added, "the U.S. Attorney's Office will determine whether federal criminal charges are supported by the evidence. If it is determined that there has been a violation of federal law, criminal charges will be sought."

The Minneapolis Police Department swiftly fired the four police officers shown in the disturbing video, in which the arresting officer appears to shove Floyd's face into the pavement with his knee for at least seven minutes on Monday evening. Several minutes into the video, Floyd's pleas for help go quiet. Medical workers lift his unresponsive body into an ambulance. Floyd was reported dead later that night.

The decision to fire the officers — who have not been officially identified — has satisfied neither Minneapolis Mayor Jacob Frey, who called Wednesday for prosecutors to press charges, nor Floyd's family members, who want the officers specifically charged with murder.

It also hasn't satisfied protesters in Minneapolis, where throngs of people turned out for a second straight day of demonstrations outside the Third Precinct. For much of the day the protests were peaceful, thronged with masked chanting activists — though Minnesota Public Radio reports that tensions eventually escalated, with police using tear gas and some people tossing rocks, setting fires and looting nearby businesses.

"There's an industrial building across the street from me that's smoking," MPR News' Jon Collins reported from the scene early Thursday morning. "There's affordable housing that was being built that is still on fire ... there is a Wendy's that is completely demolished in the parking lot. Target has been looted. Cub has been looted ... and blockades everywhere."

Fires reportedly could be spotted for miles outside the city. Local police also confirmed that they are also investigating a shooting death during the melee.

In a quieter response, the University of Minnesota announced that it was immediately limiting its links with the Minneapolis Police Department, saying its Minneapolis campus would no longer contract with the department for extra security support.

"As a community, we are outraged and grief-stricken," university President Joan Gabel said in a letter to faculty, students and staff that the school shared with NPR. "I do not have the words to fully express my pain and anger and I know that many in our community share those feelings, but also fear for their own safety. This will not stand."

The outrage elicited by the video also has been evident well beyond the bounds of Minneapolis — particularly in downtown Los Angeles, where hundreds of protesters also took to the streets Wednesday. The demonstrations were such that even the Los Angeles police chief, Michel Moore, released a statementconcerning Floyd's death.

"The actions I watched in the video were incredibly disturbing and go against the basic law enforcement principle of preservation of life," he said, also acknowledging that the Los Angeles Police Department "has had our own high-profile incidents." "The lack of compassion, use of excessive force, or going beyond the scope of the law, doesn't just tarnish our badge — it tears at the very fabric of race relations in this country."

President Trump also took notice. On Wednesday, he tweeted that he had requested a federal investigation into Floyd's "very sad and tragic death."

"I have asked for this investigation to be expedited and greatly appreciate all of the work done by local law enforcement," he continued. "My heart goes out to George's family and friends. Justice will be served!"

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