DMV keeps sending notices on vehicle sold.?

I have a truck I sold somewhere around 10 years ago. I've sent multiple "Notice of Transfer and Release of Liability" forms to the DMV. However, they keep sending me Nonoperated Vehicle Notice's.

What forms do I have to fill out for the California DMV to remove my name from this vehicle?

I do not know the name of the person who bought it. The year it was sold nor the odometer reading. The person who bought it was just looking for a parts vehicle. Their plan was to gut it and scrap the rest so I doubt it exists anymore. The engine and tranny where left open to the elements and rusted out so I doubt it was ever rebuilt especially when all the good parts where gutted.

Just because there is the chance that it could still be out there I want it removed from my name.