Rivas is being held at Multnomah County Detention Center, the statement said. He is due to appear in court on Wednesday.
The Multnomah County District Attorney’s Office told CNN on Wednesday that it was “in the process of screening the case … to make an indictment decision until the court appears this afternoon.”
It was not clear whether Rivas has a lawyer.
Portland’s Jean Gerich, 77, died after being hit, the statement said.
The Oregon state coroner determined that Gerich died of blunt trauma and considered his death a homicide, according to the statement.
Gerich’s family released a police statement saying she was a longtime resident in Portland, a mother of two and a grandmother of five. “She received her first vaccination injection last week and was very happy to be back in the world,” the statement said.
“We are grateful for the good Samaritans who were there,” said the family.
Scene spanning a dozen blocks
The incident left a total of 10 people injured, including Gerich. Police said two of them were cyclists, seven were pedestrians and one of the victims could not remember whether they were inside or outside the vehicle when they were hit. The scene spanned more than a dozen blocks in southeastern Portland, on roads and sidewalks, officials said.
The police were first notified of an erratic driver at around noon on Monday, and calls about the wounded began shortly after 1 pm Eastern time.
“Additional witness reports indicate that the suspect was traveling at approximately 80-100 km / h in other parts of the neighborhood while still driving erratically,” said police.
The vehicle ended up crashing and the driver tried to run, but was stopped by civilians until the police arrived, officials said.