I am a dealer in Canada, dealer by law has to tell you everything about a car, if the car was in the accident, and if it is not indecated in the bill of sale, you can return the car or ask for some money back or sue the dealer for everything. Any staff about the car, the rental, taxi, ex-police, theft recovery, accident, frame damage, odometer reading needs to be reported to the buyer in writhing. If he even tells you the history of the car, and it is not in writing it can back and hunt him. If you sell the car as private, you dont have to do that. Plus before every sale dealer has to get the history of the car from Ministry of transportation, or DMV.