Authorities are looking to a passenger bus' black box to learn more about what caused it to crash on an icy Montana highway.

Sunday morning's accident on Interstate 90 near Clinton killed two people and injured the other 32 people onboard.

National Transportation Safety Board investigators and Montana Highway Patrol officials on Monday were downloading electronic information from the black box.

Highway Patrol Sgt. Hoffman says the data will determine the Rimrock Trailways bus' speed in the icy conditions and help authorities determine whether the driver was negligent.

Hoffman says he expects the investigation to last at least a week.

A 60-year-old woman from Illinois and a 56-year-old man from Kalispell died in the crash. One person is in critical condition and seven others are in serious condition.

Associated Press

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