; or (II) 5 or more firearms that were used in a crime under Federal, State, or local law within 3 years after the last known retail sale of the firearm are traced to the licensee within any such 12-month period. (ii) Each licensed dealer shall maintain physical records of costs incurred to implement and update the business practices, policies, and procedures, including the installation of audio and video surveillance of firearms transactions, and the implementation of an electronic record keeping system, or of physical security to prevent loss or theft of firearm inventory, and shall make the records available for inspection on the premises covered by the license until the licensee ceases to engage in the business of selling firearms. . (b) Duties of the Attorney General The Attorney General shall— (1) develop, draft, and distribute to persons licensed under chapter 44 of title 18, United States Code, materials setting forth best business practices, policies, and procedures to prevent the diversion of firearms inventory from lawful commerce, and from time to time revise the materials as appropriate