Final answer:
The duration unrecovered stolen vehicles without a VIN or OAN remain on file varies by region, but in the U.S, the NCIC keeps these records indefinitely unless the vehicle is recovered or the record is cleared.
Step-by-step explanation:
The question of how long unrecovered stolen vehicles without a Vehicle Identification Number (VIN) or Owner-Applied Number (OAN) remain on file relates to law enforcement practices and database management. Typically, there isn't a standard time frame that applies across the board since it can vary depending on the country or state's regulations and the specific law enforcement agency's policies.
However, in the United States, the National Crime Information Center (NCIC) maintains records of stolen vehicles indefinitely unless the vehicle is recovered or the record is canceled or cleared by the agency that entered the record. It is important for such records to remain accessible in order to help law enforcement recover stolen property and combat vehicle theft.