Raleigh police say they are looking for witnesses to help determine why a charter bus driven by Lorenzo Charles crashed earlier this week, killing the North Carolina State University basketball star.

Police filed a report Wednesday about the wreck Monday afternoon on Interstate 40. Police say the bus ran off the road for an unknown reason, rumbled through a grass shoulder, across an on-ramp and into a wooded area.

The report says the bus then struck several trees and went back across the road before stopping.

Police spokesman Jim Sughrue says officers remain interested in obtaining information from any witnesses.

Charles is remembered for his game-winning dunk in the 1983 NCAA championship game.