(CNN) -- The driver in Thursday's bus crash in Texas was investigated but not indicted in a fatal accident 15 years ago, according to court documents.
Two people were killed and dozens rushed to hospitals after a charter bus bound for Oklahoma overturned on a Dallas-area turnpike Thursday morning.
The driver is 65-year-old Loyd Rieve, the Texas Department of Public Safety said. He was investigated in a 1998 accident, but a grand jury declined to indict him on a charge of criminally negligent homicide.
In that accident, Rieve was driving a bus that ran over a good Samaritan helping at an accident scene.
The bus driver was injured in the Thursday accident, which occurred on the President George Bush Turnpike in Irving. It involved only one vehicle.
Department of Public Safety spokesman Sgt. Lonny Haschel told CNN the bus went off the right side of the road, hit a barrier, swerved left across lanes of traffic and struck a concrete median in a grassy area.
"It rode up on top of that concrete barrier, and then rolled on its right hand side, where it came to rest," Haschel said.
The bus, owned by Dallas-area charter company Cardinal Coach Line, was taking passengers to Choctaw Casino in Durant, Oklahoma, the department said.
Haschel said it's too early to determine a cause. Investigators are looking at several factors, including the vehicle and physical evidence on the road.
The National Transportation Safety Board said it has sent two investigators to the scene of the wreck.
"It's going to be a lengthy investigation," Haschel said.
CNN's Joe Sterling contributed to this report.