Updated 10:28 PM ET
(CBS News) Investigators are looking into a fatal roller coaster accident. A woman died at the Six Flags Over Texas amusement park in Arlington, just outside Dallas. Meanwhile, the focus now is on safety procedures at the park.
An eyewitness who was next in line said the woman asked the attendant to double check her restraints before the ride began.
"One of the employees from the park," said Carmen Brown, "she asked them to click her more than once, and the guy was like, 'As long you heard a click, you're OK.'"
Brown said the woman did not feel safe, but they let her go on the ride anyway. She was riding on the Texas Giant roller coaster reportedly with her son when she fell out of her seat and plummeted to her death. It happened Friday night at Six Flags in Arlington, Texas, where the coaster hits a high point of 153 feet. Authorities are not commenting where the woman may have fallen off.
Kanisha Howell and her daughter were also in line. "It got in the air and started coming down," she said. "I don't know if she had a seizure or what, but she fell out of the cart and just fell out of the sky."
In a statement Saturday, Six Flags said: "We are committed to determining the cause of this tragic accident and will utilize every resource throughout this process. It would be a disservice to the family to speculate regarding what transpired."
Last year, attendance at amusement and theme parks was up from the year before. Close to 132 million people visit annually with about 1 injury for every one million guests. About 59 percent of those 1,204 injuries were roller coaster related.
A day after the woman's death, Six Flags was open as usual, but the Texas Giant will remain shut pending a full investigation.
Local police say they are still looking at the possibility that the woman on the roller coaster had some sort of medical issue. In terms of national fatalities, the latest research shows there were four over the course of four years.
Update: Arlington Police Sgt. Christopher Cook told The Associated Press Saturday that the woman who had died fell from the ride and that there appears to have been no foul play. He also said the woman was pronounced dead at the scene.