A 40-year-old was arraigned on assault and other charges, accused of hitting a woman in the back of the head with a rock in Portland’s Lloyd District on Tuesday.

According to the Multnomah County District Attorney’s Office, a woman was near Northeast 2nd and Wasco Street when she saw Dwayne Anthony Simpson walking up and down the street.

When she turned her back to him, she felt a sharp impact on her head, authorities said. She also hit her head on a concrete barrier when she fell to the ground.

Witnesses said they saw Simpson hit her in the head with a large rock. She reportedly was motionless on the ground for two minutes after the attack.

The woman was taken to a hospital; there’s no immediate word on her current condition.

Police officers arrested Simpson and say they found the rock he allegedly used to hit the woman, describing it as about the size of a basketball and weighing 34.5 pounds.

On Wednesday, Simpson was arraigned on three charges – first-degree attempted assault, second-degree assault, and unlawful use of a weapon.

Simpson will remain in custody until further order from the court, the district attorney’s office said.