A motorcyclist suffered serious injuries in a suspected DUI collision with a pickup truck Monday afternoon at a busy Santee intersection, according to the San Diego County Sheriff's Office.

Deputies responded at approximately 1:50 p.m. to reports of a crash at North Magnolia Avenue and the on-ramp to State Route 67, where they found the motorcyclist on an embankment next to the roadway with severe injuries. A bystander at the scene joined deputies in providing first aid, including applying a tourniquet to control the rider's bleeding.

The motorcyclist was transported to a trauma center for treatment. The driver of the pickup truck remained at the scene and was evaluated by paramedics. Authorities said they believe driving under the influence was a contributing factor in the collision.

The Santee Sheriff's Station is asking anyone who witnessed the crash or has information to call 619-956-4000.