MINNEAPOLIS — The Minneapolis police officer who knelt on George Floyd’s neck was arrested and charged with murder Friday, and authorities imposed an overnight curfew to try to stem three nights of often-violent protests that left dozens of stores burned and looted.

Derek Chauvin, 44, was charged with third-degree murder and second-degree manslaughter in the case. He was also accused of ignoring another officer at the scene who expressed concerns about the black man as he lay handcuffed on the ground, pleading that he could not breathe. Floyd had been arrested on suspicion of using a counterfeit bill at a small grocery store.

An attorney for Floyd’s family welcomed the arrest, but said he expected a more serious murder charge and wants all four officers involved to be arrested.

Hennepin County Attorney Mike Freeman said more charges were possible. He said the investigation into the other three officers continues, but authorities “felt it appropriate to focus on the most dangerous perpetrator.”

Meanwhile, Minneapolis Mayor Jacob Frey declared a curfew from 8 p.m. to 6 a.m. on Friday and today.

According to the criminal complaint, Chauvin allegedly disregarded the concerns of another officer, who wanted to roll Floyd onto his side as he was being held down.

The papers also said that an autopsy revealed nothing to support strangulation as the cause of death. The exam concluded that the combined effects of being restrained, potential intoxicants in Floyd’s system and his underlying health issues, including heart disease, likely contributed to his death.