Prosecutors charged a Minneapolis police officer accused of pressing his knee against George Floyd’s neck with second-degree murder on Wednesday, and for the first time, levelled charges against three other officers at the scene, according to criminal complaints.

The updated criminal complaint against Derek Chauvin says the officer’s actions were a “substantial causal factor” in Floyd’s death.

“Officer Chauvin’s restraint of Mr Floyd in this manner for a prolonged period was a substantial causal factor in Mr Floyd losing consciousness, constituting substantial bodily harm, and Mr Floyd’s death as well,” the criminal complaint said.

The complaints against the other officers allege that they aided and abetted in Chauvin’s actions.

Minnesota Attorney General Keith Ellison updated the complaint against Chauvin to add a charge of unintentional second-degree murder in addition to the earlier charges.