The sheriff's office received a call at about 12:15 p.m. reporting shots fired in the area of Mariposa and California streets.
When deputies arrived they found evidence of a shooting, but the victim wasn't there.
Meanwhile, about 10 minutes after the initial call, the sheriff's office received a second call from the California Highway Patrol reporting that officers had located a shooting victim near the Willow Avenue exit from westbound Interstate Highway 80, Lee said.
The male victim was taken by helicopter to a local hospital. Lee did not know his age or condition.
Lee did not know how the victim got from the scene of the shooting to the highway, but said it isn't unusual for friends or family members of shooting victims to take victims to the hospital in a private vehicle instead of waiting for an ambulance to arrive.