Chinese police have taken down a counterfeit salt ring involved in a case worth more than 20 million yuan (about $3.22 million) and covering seven cities and provinces.

The investigation began in December 2014 when local police in Taizhou city, Jiangsu province in east China, discovered industrial salt being marketed as table salt. The fraudulent salt contained no iodine, despite claims to the contrary on its packaging. As the investigation continued, Taizhou police discovered similar "salt" in many grocery stores in suburban areas being sold to household consumers, small restaurants, food processing shops and company canteens.

Police later discovered that the fake salt came from Daxing district in Beijing, where a suspect surnamed Wang had registered an industrial salt company to disguise the illegal business. Except for limited local and online purchases, most of the salt was sold in Jiangsu, Shandong and Anhui.

The criminal gang was organized in a family structure, and produced more than 20,000 tons of fake salt. On April 2, 2015, 22 major suspects were arrested in various locations, an effort coordinated by the Public Security Ministry.

"It doesn't require any technology at all," said one suspect. "All you need to do is pack up industrial salt materials and sell them. You buy industrial salt at 400 to 500 yuan per ton, and when it is 'transformed' into table salt, you can sell it for 800 to 1000 yuan per ton."