By Lenzy Krehbiel-Burton

STILLWATER, Okla. (Reuters) - A man who was watching the Oklahoma State University homecoming parade when a car plowed into a crowd and killed four people said the crash sounded like a bomb went off, transforming a festive mood into one of horror.

Mark McNitt was standing beside his stepfather, Leo Schmitz, 54, when the sedan careened into a throng near the end of the annual parade on Saturday at the university in Stillwater, about 65 miles (105 km) southwest of Oklahoma City.

Four people died, including a 2-year-old boy, while at least 47 others were injured. Five of them, including Schmitz, were in critical condition.

"All I remember was a gush of wind and then the sound," McNitt said at a news conference, recalling when the gray Hyundai Elantra jumped the curb, mowing down dozens of men, women and children.

"The only thing I can relate it to is some type of bombing," said McNitt, who said he had minor injuries. "The screaming ... and a lot of chaos."

Onlookers rushed to help the injured, he said. Police and emergency medical personnel were nearby, at the end of the parade route, before the start of an Oklahoma State University football game, he said.

The driver, identified as Adacia Avery Chambers, 25, of Stillwater, was expected to make an initial appearance in Payne County District Court on Monday, police said on Sunday.

Chambers was taken into custody on suspicion of driving while under the influence of alcohol or narcotics, said Stillwater Police Captain Kyle Gibbs. Police were awaiting results of a blood test administered after the crash.

Chambers worked at Freddy’s Frozen Custard & Steakburgers in Stillwater, the restaurant said on Sunday.

Three adults - identified as Nakita Prabhakar, 23, of Edmond, Oklahoma; Bonnie Jean Stone, 65; and Marvin Lyle Stone, 65, both of Stillwater - were pronounced dead at the scene, police said.

A toddler, who was not identified, died later Saturday. Family members identified him as Nash Lucas, according to KOTV, a local television station.

Story continues

Prabhakar, originally of Mumbai, India, was a graduate business student at the University of Central Oklahoma in Edmond, the school said, identifying her as Nikita Nakal. The university could not be reached immediately to clarify the discrepancy.

Stone was a professor of agricultural engineering at OSU, according to the school's website. He retired in 2006 and founded the Marvin and Bonnie Stone Endowed Scholarship Fund with his wife the following year.

Authorities did not release additional information about Chambers, except that she lived in Stillwater. Gibbs said she did not appear to be an OSU student.

Floyd Chambers, 47, the suspect's father, told The Oklahoman newspaper his daughter lived with her boyfriend in Stillwater. He described her as timid and not an alcoholic.

“They’re going to paint her into a horrible person but this is not (her),” he said.

(Additional reporting by Laila Kearney in New York; Writing by Frank McGurty; Editing by Clelia Oziel and Jeffrey Benkoe)