Transcript for Ex-Minneapolis police officer charged in deadly arrest
Reporter: Good evening. It's great to have you with us on a Friday night. Another difficult week in in country and authorities are bracing for what they fear could be another difficult night. There are curfews in place in the twin cities amid news of the arrest tonight in the death of the George Floyd. The former officer churched with murder and manslaughter. Three other fired officers are under investigation. The final moments of George Floyd's life. Officer Derek chauvin seen here with his knee on Floyd's neck. Floyd can be heard saying I can't breathe. Prosecutors say head his knee on his neck. Two officers appearing to help pin down Floyd while in handcuffs. Overnight, the unsettling images. The protesters setting fire to the police department's third precinct. It had been evacuated. 170 building damaged. Deploying National Guard to maintain peace amid the curfews tonight. We are monitoring images as we are on air of the growing outrage across the country. Protests right now in New York, Atlanta, Washington, D.C. Among other places. Just a short time ago president trump explaining his words in a tweet overseas night, saying he did not know the history behind them, saying when the looting starts the shooting starts. Joe Biden delivered a message saying he talked to George Floyd's family and the president saying he talked to George Floyd's family too, revealing what he said to them. We have it all covered on a Friday night. We begin with Alex Perez in Minneapolis. Reporter: Tonight, the white former Minneapolis police officer at the center of a national firestorm Derek chauvin arrested and charged with the murder of George Floyd. Please. Please, I can't breathe. Please, man. Please, somebody help me. Reporter: That horrific video enflaming a nation showing chauvin digging his knee into Floyd's neck while Floyd is handcuffed and the crowd begs him to stop. He's not resisting or anything. Reporter: The defendant had his knee on Mr. Floyd's neck for 8 minutes and 46 seconds in total. 2 minutes and 53 seconds of this was after Mr. Floyd was non-responsive. Police are trained that this type of restraint with a subject in a prone position is inherently dangerous. Police initially said Floyd resisted officers and noted he appeared to be suffering medical distress. Former Minneapolis police officer Derek chauvin has been charged by the hennepin county's attorney office with manslaughter and third-degree murder. We are in the process of continuing to review the evidence. There may be subsequent charges later. Reporter: Our affiliate KSTP there as Floyd's girlfriend reacted to hearing the news. This is a piece of justice. This is the first piece, and it needed to -- it needed to be done. It's time. Reporter: Three other officers involved in arresting Floyd, tou Thao, Thomas lane, and J. Alexander kueng were also fired. New video shows lane and keung also pinning down Floyd as he screams while in handcuffs. Please! Please let me stand. I'm not going to speculate today on the other officers. They are under investigation. I anticipate charges. Reporter: The news comes after a night of rage across the twin cities and the country. What's his name? George Floyd! What's his name? George Floyd! Reporter: Police fleeing and protesters cheering as the a police precinct house goes up in flames. Alarms and sprinklers activated inside. More than 500 National Guard soldiers deployed. The protests spilling into other cities from Phoenix and Los Angeles -- to New York City. Dozens arrested there. In Denver, a driver nearly running over a protester. Watch out! Reporter: The twin cities still burning at daybreak. This fire is unattended at this moment. Reporter: Many buildings here like this one reduced to just a shell. You can see over there a broken water main, and in the distance, those officers working to keep the peace. Fires still burning behind them. Protesters wanting their voices heard. What we want is for the nation to hear us out and understand that this is not no game. I'm sorry? You're under arrest. Okay. Do you mind telling me why I'm under arrest? Reporter: State police arresting a CNN reporter and his crew. They were quickly released. George Floyd in his own words. A newly discovered video shows him speaking of breaking the cycle of violence he saw among young people. One day it's gonna be you and you're going up or you're going down. Reporter: Floyd's second grade teacher talking to our station KTRK. As teachers, we teach our children to go, to find helpers when they are in trouble and to find the policemen. And I wonder now, and have been for some years, what do we teach our young black men? Who are the helpers for the young black men? Let's get back to Alex Perez. He's with us live from Minneapolis tonight. Alex, I know the lawyer for the family of George Floyd is now weighing in on the charges? Reporter: Yeah, David, Floyd's family says they expect and want to see first-degree murderer charges. They also want to see the other officers involved arrested. You can see a lot of buildings here are still burning. The governor has called for that curfew here in the twin cities this weekend. It starts at 8:00 tonight. David?
This transcript has been automatically generated and may not be 100% accurate.