Stumbled upon this today while searching around:

NICB's VINCheck is a service provided to the public to assist in determining if a vehicle has been reported as stolen, but not recovered, or has been reported as a salvage vehicle by cooperating NICB members. To perform a search a Vehicle Identification Number (VIN) is required. A maximum of five VINCheck searches can be conducted within a 24 hour period.

https://www.nicb.org/theft_and_fraud_awareness/vincheck