Gabe Flores said he was next in line at the amusement park.

"Me and my girlfriend were at the gates and the next ones to get on the ride ... the cars came in and there was a man and a woman in the front," he said. "The man was saying, 'let me out, let me out, my mom fell off.' "

The man and woman were distraught and speaking in raised tones, said Flores, who lives in Benton, Texas.

"There's a turn that's pretty steep, and the person behind her empty seat said she fell out therejust flew out," he said.

Flores did not see her fall, but park visitors told CNN affiliate WFAA they did.

"She goes up like this," Carmen Brown told the affiliate, raising her hand up in the air. "Then when it drops to come down, that's when it released and she just tumbled."

Early attention was being focused on witnesses reports that the womans safety restraint had come undone.

Carmen Brown of Arlington was waiting in line as the victim and her son were being strapped in for the ride.

She was right in front of us, but we werent on the ride, she said. The lady basically tumbled over.

Brown said the victims young son was in the seat in front of his mother.

We heard her screaming. We were, like, Did she just fall?

Brown said she didnt believe that the woman had been secured in her seat correctly.

Brown said the victim expressed concern to a park employee that her harness only clicked once when it was lowered into place, unlike the multiple clicks heard when others were strapped in.

He was basically nonchalant, Brown said. He was, like, As long as you heard it click, youre fine. Hers was the only one that went down once, and she didnt feel safe. But they let her still get on the ride.

Investigators were interviewing witnesses on the ride, some of whom reported that the woman had been thrown from the roller coaster as it rounded a turn.