The county government in every state updates the tax lien affected properties list regularly. If the property owner does not pay the income taxes within a stipulated period the government seizes the property. The seized property is now a lien and auctions are performed on it to retain the owed taxes. Investors can attend in the auction process and purchase any properties by winning the bid. The rules and regulations are different from one county to another. It is best to do a legal clarification from the state county before planning to purchase a lien.
Source: tax lien properties