The Illinois Department of Natural Resources says four northern Illinois businesses have been cited for violating state law by selling products containing shark fins.
The companies received a total of 20 citations last Friday.
Rafael Gutierrez is chief of the DNR's Office of Law Enforcement. He says investigators bought products from six Chicago businesses late last year, including shark fin soup in a restaurant, canned shark fin soup, frozen shark fin and soup kits.
DNA analysis conducted at The Field Museum in Chicago confirmed the products contained shark.
Last week, officers returned to the businesses to issue citations to four of them. They were unsuccessful in serving two, who will be cited later.
Illinois in 2012 became the first non-Pacific state to enact a shark fin ban.