The roller coaster from which a man with cerebral palsy (search) was flung to his death will remain closed until an investigation is completed, an amusement park official said.

Stanley J. Mordarsky, 55, fell Saturday from the Superman Ride of Steel coaster at Six Flags New England (search) in Agawam, about 90 miles west of Boston, park officials said.

Christine M. Cole, spokeswoman for the Department of Public Safety, would not release any information about whether mechanical failure, a mistake by an operator or actions by Mordarsky caused his death. She said a full report is due out later this week.

The park is closed Monday through Thursday in May until Memorial Day, but the roller coaster will stay out of operation until the investigation is finished, said Mary Ann Stebbin-Burns, a spokeswoman for the park.

Mordarsky had difficulty walking but park officials said he was able to board the roller coaster by himself. Under the federal Americans With Disabilities Act (search), officials said, disabled people must be allowed on rides if they can board by themselves.

Park officials said Mordarsky tumbled from the roller coaster as the ride neared the end of its two-minute run. Witnesses described him coming out of his harness as the ride hit a curve.

His mother, Germaine Mordarsky, 82, said Sunday that she did not believe her son's physical problems could have caused the accident. He had a season pass to the park and left the motorized scooter he normally used in his van and walked to rides, she said.

Superman Ride of Steel is 20 stories high and its cars can reach 80 mph during its mile-long run. Riders experience 10 seconds of weightlessness, according to the Six Flags' Web site.

Cerebral palsy is caused by brain damage, usually before birth, that impairs the ability to control muscle movement. An estimated 500,000 U.S. children and adults are afflicted.

Cole said the last death on a Massachusetts amusement park ride was in 1988. Permanent amusement parks do their own daily inspections, and must give the state inspection reports by independent, state-certified inspectors at the start of each season. Otherwise, state safety inspectors are called in when there is an accident or a fatality, she said.

Six Flags Inc., based in Oklahoma City, operates 31 parks in North America and Europe.