A woman who drove into a crowd of spectators at a homecoming parade in the US state of Oklahoma, killing four people, has been charged with second-degree murder.
But her lawyer said Adacia Chambers, 25, was not drunk at the wheel of her car, as police suspected, when she hit the people in Stillwater.
“I absolutely can rule out alcohol,” said attorney Tony Coleman, adding his client might have mental problems.
Ms Chambers is due in court on Monday.
Witnesses described dozens of bodies being flung into the air, after Ms Chambers’ car hit a parked police motorbike before ploughing into spectators at the Oklahoma State University homecoming parade.
Three adults and a two-year-old boy died, with nine children among about 50 people injured. Five people remain in critical condition.
Ms Chambers was detained on suspicion of driving under the influence of alcohol. Police are still awaiting the results of blood tests.
Mr Coleman said she was not intoxicated but added: “I have deep concerns about her competency at this point. I’m not a psychologist or psychiatrist, but I can tell you she’s suffering from mental illness.
“She doesn’t remember a whole lot about what happened. There was a period where I think… she could have even blacked out,” the attorney said.
The four counts of second-degree murder each carry a possible penalty of 10 years to life imprisonment.
‘A lot of screaming’
One eyewitness likened the impact of the vehicle to a bomb.
“All I remember was a gush of wind and then the sound,” said Mark McNitt, whose father-in-law Leo Schmidt was critically injured.
“The only thing I can relate it to is some type of bombing,” he added, “the screaming… a lot of screaming.”
Ms Chambers lives in Stillwater, a town 65 miles (105 km) north-east of Oklahoma City, but is not believed to be an OSU student.
Her father, Floyds Chambers, told The Oklahoman newspaper his daughter was timid and not an alcoholic.
“They’re going to paint her into a horrible person but this is not (her),” he told the paper.
A vigil to remember the victims was held at the OSU campus on Sunday evening.