Russian Security Service (FSB) head Alexander Bortnikov said that the explosion of a homemade bomb of up to 1kg of TNT equivalent was the cause of the crash of the Kogalymavia flight 9268 A321 airbus over Sinai, Egypt, while en route from Sharm El-Sheikh to St. Petersburg on October 31.

The investigation found traces of an explosive material in personal items and parts of the plane. The explosion of a home-made device would explain the scattering of the plane’s fuselage across a wide area.

Russia is offering $50 million for information on those who might be involved in the terrorist act that led to the plane breaking up in mid-air.

Russian media reports state that security officers suspect the bomb was most likely planted inside the hold of the plane by a Sharm el-Sheikh baggage handler. In Egypt, two airport employees were held on Tuesday morning on suspicionof aiding those who planted bomb on Russian plane, reports Skai News.