The poisoned children were vacationing at an unregistered private summer camp.
He carried out his activities in the Kirov region without complying with the requirements of the law.
The camp, which was not included in the regional register of children's recreation and health organizations, was closed, RIA Novosti reports.
The investigations were initiated by the regional prosecutor's office and investigative department.
During the raid, inspectors discovered signs of entrepreneurial activity that were harmful to the health of children and employees.
The camp was closed due to violations of current legislation after four children were poisoned.