Probe into gas blast at Achinsk refinery in the Krasnoyarsk region.
'The fate of three people is currently unknown'. Picture: Yulia Lebedeva, Channel 7 Krasnoyarsk
Seven other victims were hospitalised as a result of the tragedy which saw a fire sweep through the oil refinery.
'As a result of the fire five people were killed,' the Investigative Committee said in a statement. 'The fate of three people is currently unknown'.
The Siberian refinery is owned by state oil giant Rosneft.
The refinery processes 140,000 barrels a day and the blast was in a 'fractionation unit'.
Taken from his mountain grave in Mongolia, the body of Tsorzh Sanzhzhav had been destined for the black market.
Photographs show red lights hovering about the ground and then moving vast distances in less than one minute.