(Litchfield)--Authorities are investigating a double decker bus accident that killed at least one person, and injuring several. According to Illinois State Police, the megabus was trasporting 65 people from Chicago to St. Louis when the bus crashed into a concrete bridge pillar along Interstate 55, north of Litchfield.

According to Captain Scott Compton, half of the 65 passengers were injured. Compton says 12 people received serious injuries, with 5 to 10 people suffering critical injuries.

One person, 24 year old Aditi Avhad of India, was killed as a result of the accident. The cause of the accident is under investigation. Interstate 55 was shut down as a result of the accident.