Washington, Muharram 13, 1437, October 26, 2015, SPA -- Sixteen people remained in hospital Sunday recovering from injuries they suffered when a car plowed into a group of spectators along a parade route in the US state of Oklahoma, according to dpa. Five of the 16 people being treated were in critical condition, authorities said. Four people, including a 2-year-old boy and a 65-year-old retired professor, were killed Saturday in the incident in Stillwater, Oklahoma, during a homecoming parade at Oklahoma State University. A 25-year-old woman was arrested for driving under the influence, police said. But a lawyer representing Adacia Chambers said alcohol was not a factor. Tony Coleman said when he interviewed Chambers she "was entirely blank" and had no sign of being under the influence. "In my opinion Chambers suffers from a mental illness," he said on Fox News. "Exactly what type is yet to be determined." She has been charged with four counts of second-degree murder, Stillwater Police Department said, according to the university's news portal ocolly.com. She could appear in court as early as Monday and may face additional charges, news reports said. People who witnessed the incident described debris and bodies flying in the air. "I never saw her brake. She never tried to stop. She accelerated," Krystina Dodson said on Fox News. About 30 other people were treated for minor injuries, according to Oklahoma media reports. Officials at the University of Oklahoma Medical Centre in Oklahoma City said several of the injured people were being treated at the hospital's trauma centre. Jeffrey Bender, a trauma surgeon at the medical centre, said the facility was prepared because it had run mass casualty drills in preparation for tornadoes, which often strike in the state. Burns Hargis, the president of the university, said the community was devastated and heartbroken by the incident. "The Oklahoma State University homecoming parade is the most wholesome of events and to have it marred in such a way is incomprehensible," he said. --SPA 03:39 LOCAL TIME 00:39 GMT www.spa.gov.sa/w