At the time specified in the notice of sale, if the animal or fowl so impounded is not redeemed, the chief of police or his designated agent shall sell the same to the highest bidder for cash. Upon payment by the buyer to the chief of police of the cash amount of the bid, the buyer at the sale becomes the lawful owner of the animal and the previous owner, whether known or unknown, is fully divested of title to the said animal or fowl. Under no circumstances may any official or employee of the city become interested in, directly or indirectly, the purchase of the animal or fowl to be sold. (1982 Code)