LITCHFIELD, Ill. (AP) - Authorities say a blown tire appears to have caused the crash of a double-decker bus on a southern Illinois highway in which one passenger was killed and dozens were injured.
   
State Police Lt. Louis Kink said Friday that the investigation into Thursday's crash near Litchfield could take weeks, but that there doesn't appear to have been driver error.
   
The packed Megabus veered into a highway overpass support pillar about 55 miles northeast of St. Louis. A University of Missouri graduate student who was sitting above the driver was killed.
   
Kink says 47 people were taken to hospitals. He didn't know how many were critically injured but said none of the injuries appear to be life-threatening.
   
The bus was headed from Chicago to Kansas City, Mo.

(Copyright 2012 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.)

Earlier story:

LITCHFIELD, Ill. (AP) - State police in Illinois say a preliminary report could be finished by later today on the cause of yesterday's crash of a double-decker bus into a highway overpass in southern Illinois.
   
The crash killed one person -- a 25-year-old woman from India who was a grad student at the University of Missouri. More than three dozen others were taken to hospitals.
   
A bus line official says the bus had been manufactured last year and passed a company safety inspection a few days ago.
   
Investigators are looking into passenger reports that the bus blew a tire just before the crash.
   
The bus was on its way from Chicago to Columbia, Mo., and then on to Kansas city. There were 81 passengers on board.
   
Passengers are giving harrowing accounts of the crash. Sixteen-year-old Baysha Collins says she was thrown from her upper-level seat to a stairway leading to the lower level. She says she heard "a lot of screaming and crying." The front end was so mangled, crews had to use ladders to rescue people trapped inside.
   
A Chicago man says passengers began helping each other almost immediately. He says panic was followed by "total calm" as people carried other passengers off the bus.

(Copyright 2012 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.)