"Retribution for war crimes is inevitable."Who was Lieutenant General Igor Kirillov?Born on July 13, 1970, 54-year-old Kirillov was the head of the Russian Armed Forces' radiation, chemical, and biological defense troops (RKhBZ).According to the think tank and research group Global Security, the RKhBZ are ostensibly "special troops designed to perform the most complex tasks of protecting troops and the population, requiring the use of special equipment.""They consist of units and divisions for detecting nuclear explosions, radiation and chemical reconnaissance, special processing, aerosol countermeasures, flamethrower, etc," it adds.A Russian RS-24 Yars thermonuclear armed intercontinental ballistic missile arrives for a military parade rehearsal ahead of Russia's Victory Day celebration in Moscow, Russia, on May 5, 2024. (Contributor/Getty Images)In Ukraine, Kirillov became best known for his alleged role in the use of chemical weapons by Russian forces against Ukrainian troops.Chemical weaponsKirillov's involvement in chemical weapon attacks predates the full-scale invasion of Ukraine.In 2018, Kirillov defended Moscow against accusations that Russia and Syria were tampering with evidence and blocking access to the site of a chemical weapons attack that killed more than 40 civilians in the Syrian town of Douma in 2018.A report from the Organisation for the Prohibition of Chemical Weapons later found the Syrian regime of Bashar al-Assad had likely carried out the attack, despite Russia long-claiming otherwise, and spreading debunked conspiracy theories to try and shift blame away from their ally.Recent witness testimony provided in the wake of the fall of Assad provided further evidence that Syrian and Russian authorities lied and intimidated locals to try to suppress what actually happened.Russian chemical weapons in UkraineMoscow's forces have been increasingly deploying gas attacks against Ukrainian troops, a Kyiv Independent investigation from August found, and Kirillov has since been sanctioned by the U.K.