So the world has been very aware of the Russian oligarch gangsters from the time of Yeltsin. Many are on the run abroad, with London being a favourite destination. A lot of these are hated by the Russian people and government although it is thought Putin has a number of "tame" oligarchs whom his administration has some hold over.
Not so widely known is how Ukraine has its own oligarch problem, including corrupt government officials, that are turning it into just as much of a gangster state. Again London is a favourite destination for their ill-gotten gains due to notoriously lax regulation of financial and property transactions since the time of Thatcher. A money-laundering paradise with 1000s of high-value real-estate properties being bought up as this BBC documentary investigates:https://www.youtube.com/watch?v=kCjuEkCHiPw