STILLWATER, Okla. — A 25-year-old woman accused in the deaths of four people at the Oklahoma State homecoming parade is scheduled to appear in court today, after witnesses said she drove her car into spectators with such force that she sent bodies flying into the air.

Adacia Chambers was initially arrested on suspicion of driving under the influence after the crash Saturday morning in Stillwater that also injured dozens of people. But late Sunday, police said Chambers was also being held on four counts of second-degree murder.

Chambers of Stillwater is scheduled to appear today in Payne County District Court. She has yet to be formally charged.

A police statement did not explain the reasons for the new charges.

Tony Coleman, Chambers’ attorney, said at a news conference in Oklahoma City he believed his client suffers from a mental illness and there was no indication she was drinking before the crash. Police are awaiting blood tests to determine whether Chambers was impaired by drugs or alcohol.

“I absolutely can rule out alcohol,” Coleman said.

He said he spoke with Chambers for about an hour.

“During that entire interview, I was not satisfied at all that I was communicating with a competent individual,” Coleman said.

Chambers, who had been at work before the crash, doesn’t remember much of what happened, only recalling being extremely confused as she was removed from the car, the lawyer said.

“She could have even blacked out,” Coleman said.

Chambers’ father, Floyd Chambers, told The Oklahoman newspaper Saturday he couldn’t believe his daughter was involved and said she was not an alcoholic.

Coleman said Chambers’ family was “absolutely devastated.”

Witnesses described a scene of chaos as bodies flew into the air from the impact and landed on the road. Three adults and a 2-year-old boy were killed and at least 46 others were hurt, including at least four critically injured.

Authorities have not released the identity of the child who was killed. The dead adults were identified as Nakita Prabhakar Nakal, 23, an MBA student from India at the University of Central Oklahoma in Edmond, and a married couple, Bonnie Jean Stone and Marvin Lyle Stone, both 65, of Stillwater. Marvin Stone was a retired professor of agricultural engineering, who had been popular with students, a colleague said.

“He was loved by students and one of the best teachers we had,” said Ron Elliott, the former head of the Biosystems and Agricultural Engineering Department at OSU. “He just really had a gift for connecting with students and helping them learn.”