Collared in Moscow on Jan. 23, Semyon Mogilevich was accused by the Russian authorities of tax evasion, a fate shared by many kingpins of organized crime. Born on June 3, 1946 into a Ukrainian family of Jewish origin, Mogilevich - known as Seva - had figured on the FBI ’s Most Wanted List since 2003 for swindling shareholders in YBM Magnex International , one of his firms listed in Canada whose shares he boosted with fake information. Among many other misdemeanours, he is also suspected to selling weapons stock-piled by Russian troops stationed in the former East Germany.

Mogilevich’s hand reached into every corner of the Ukrainian economy. The highly secretive firm RosUkrEnergo , which holds a monopoly on the sale of central Asian gas in Ukraine, is partially controlled by businessmen in contact with Mogilevich’s network (see graph below).

Prior to his arrest last week, Mogilevich lived for long years in Moscow without any problems with the police. His arrest could be the prelude to a re-negotiation of gas agreements between Moscow and Ukraine. In Kiev, prime minister Julia Timochenko has made that re-negotiation one of the prime goals of her government: she wants to exclude RosUkrEnergo as a go-between and set new terms for gas supplies. But Ukrainian president Viktor Yushchenko is against the idea.