Nine videos were shot imitating a chemical attack against civilians in Idlib, they will be used to hold the Syrian government responsible for the attacks. The videos were shot with the “White Helmet propaganda Islamist organisation”.
During the last decades, neither Russia nor the Soviet Union has been engaged in extrajudicial killings; neither in the territory of Russia, nor abroad.
Killing opponents of the regime was a practice familiar to the USSR, see e.g. the case of Leon Trotsky. There has also been a case of murdering a former Russian spy already - in 2006, Alexander Litvinenko was poisoned by two Russians in London. As the UK public inquiry has found, "the FSB operation to kill Mr Litvinenko was probably approved by [Nikolai] Patrushev [head of the security service in 2006] and also by President Putin”: https://www.theguardian.com/world/2016/jan/21/alexander-litvinenko-was-probably-murdered-on-personal-orders-of-putin