It is unlawful for any person, firm or corporation engaged in the business of a pawnbroker to buy any property of any kind or receive the same as a pledge of security, which property is distinctly and plainly marked as being the property of any firm or corporation or person other than the party offering to sell or pledge the same, unless the party offering to sell or pledge the same shall show satisfactory evidence in writing that he is the lawful owner of the property or has been granted permission by the owner to pledge the property. Failure to require such written evidence shall be prima facie evidence of guilty knowledge on the part of the pawnbroker, his agents or employees, that the party offering to pledge or sell the same is not the rightful owner thereof and is a violation hereof. (Prior code § 8-1-6)