Russian police on Monday arrested the maker of ‘Mister Cider’, after 18 people across three jurisdictions died from drinking his products. Another 17 people were hospitalized in serious condition, and the authorities fear the death toll may yet rise.

“preventive raids on all points of sale of alcohol” in the region, while Rospotrebnadzor banned the sales of all ‘Mister Cider’ products in Russia. Police have set up roadblocks to check beverage trucks for contraband, while inspectors and officers combed the warehouses across the country. Contaminated alcohol was found as far west as Nizhny Novgorod and as far east as Izhevsk.

While the authorities have not yet revealed what caused the mass poisoning, the prime suspect is methanol, a type of alcohol highly toxic to humans. The symptoms have been listed as weakness, headache, vomiting, shortness of breath, blurred vision, low blood pressure and fainting, said deputy head of Udmurtia Elvira Pinchuk, urging everyone affected to “see a doctor as soon as possible.”