MINNEAPOLIS (AP) — Prosecutors charged three more police officers Wednesday in the death of George Floyd and filed a new, tougher charge against the officer at the center of the case, delivering a victory to protesters who have filled the streets from coast to coast to fight police brutality and racial injustice.

The most serious charge was filed against Derek Chauvin, who was caught on video pressing his knee to Floyd’s neck and now must defend himself against an accusation of second-degree murder.

The three other officers at the scene were charged for the first time with aiding and abetting second-degree murder and second-degree manslaughter.

All four were fired last week.

If convicted, they could be sentenced to up to four decades in prison.

Chauvin was initially charged with third-degree murder and second-degree manslaughter. Those charges still stand.

The new second-degree murder charge alleges that Chauvin caused Floyd’s death without intent while committing another felony, namely third-degree assault. It carries a maximum penalty of 40 years in prison, compared with a maximum of 25 years for third-degree murder.

The other officers — Thomas Lane, J. Kueng and Tou Thao — face the same maximum penalties for aiding and abetting.

The additional charges were sought by Minnesota Attorney General Keith Ellison, who called the protests unleashed by the death “dramatic and necessary” and said Floyd “should be here and he is not.”

“His life had value, and we will seek justice,” said Ellison, who cautioned that winning convictions would be hard and said that public pressure had no bearing on his decisions.

Hundreds of protesters were in New York City’s Washington Square Park when the charges were announced.

“It’s not enough,” protester Jonathan Roldan said, insisting all four officers should have been charged from the start. “Right now, we’re still marching because it’s not enough that they got arrested. There needs to be systematic change.”