Minnesota’s Attorney General on Wednesday increased the charge against fired Minneapolis police officer Derek Chauvin to second-degree murder in the death of George Floyd, a case that has led to more than a week of nationwide unrest and sometimes violent protests against the explosive issue of police brutality against African Americans.

Minnesota Attorney General Keith Ellison also charged the three other fired officers at the scene with aiding and abetting murder.

Chauvin was fired and charged last week with third-degree murder, after kneeling on the neck of George Floyd who begged for air.

The new second-degree murder charge can carry a sentence of up to 40 years, 15 years longer than the maximum sentence for third-degree murder.

Tens of thousands of Americans have taken to the streets in cities across the country for protests that have at times led to widespread vandalism and looting.

National Guard troops lined the steps of the Lincoln Memorial in Washington D.C.

In Los Angeles, numerous demonstrators who stayed out after the city’s curfew were arrested.

And, in New York City, looting of some stores in Manhattan gave way to relative quiet by night’s end.