A fierce fire that broke out at a hotel in Russia's western Perm Region on Tuesday, has killed six people including three children.
Local investigative committee said in a statement that a criminal probe was launched into the case.
There were so visible signs of violence, according to preliminary information.
The flame has been completely extinguished. A group of experienced and qualified criminal investigators is working at the scene, reports Xinhua news agency.
All possible circumstances of the incident are established, including the causes and conditions that led to the tragedy, added the statement.