The case was opened after the discovery of gross violations in the Pioneer mine. The rock collapse trapped 13 miners.
The accident occurred on March 18. It was previously reported that a video camera detected water in the mine. It is believed that the water was caused by a leak in the ventilation system. The mine is located in the Zeya municipal district of Rostekhnadzor, in the Amur region of Russia. The investigation is ongoing and no arrests have yet been made, the prosecutor's office said.