It happened just after 11 Monday night on Highway 145. The collision blocked off traffic in both directions until Tuesday morning.
Investigators took measurements of the scene along with other evidence to determine who is to blame for the accident.
It appears the 25-year-old pedestrian was in the road when an on duty Sheriff's deputy struck and killed her.
Officers say Kristle Clowers was alone and wearing dark clothes when she was hit.
Ken Antonetti with the California Highway Patrol said, "Whether she stumbled out in front of his patrol car or was already within the lane. That's one of the questions, as well as the toxicology report is being done on the subject to see if there was any issues with alcohol and or drugs."
The deputy, identified as Kurt Rossi, gave the woman CPR, but she died at the scene. Investigators say the deputy was very upset and has been interviewed about what happened.