Sigalert issued for SR-91 west in Riverside due to fatal motorcycle crash

A fatal collision involving a motorcycle rider prompted a Sigalert for State Route 91 in Riverside Tuesday morning. 

The crash occurred just before 8 a.m. near the Van Buren Boulevard exit, though the circumstances leading up to the collision were not immediately known. 

The motorcyclist's identity was not immediately known. 

As they investigated, California Highway Patrol officers issued a Sigalert for the area, with an unknown duration. Traffic was being diverted away from the scene of the crash. 

This is a developing story. Check back for details.