Semion Yudkovich Mogilevich is a Jewish Ukrainian-born Russian organized crime boss. He quickly built a highly structured criminal organization, in the mode of an American mafia family; many of the organization's 250 members are his relatives. He is described by agencies in the European Union and United States as the "boss of all bosses" of most Russian Mafia syndicates in the world, he is believed to direct a multibillion-dollar international criminal empire and is described by the Federal Bureau of Investigation (FBI) as "the most powerful and dangerous gangster in the world," with immense power and reach at a global scale, and connections to prominent government, military, and law enforcement officials, and powerful politicians around the world. He has been accused by the FBI of "weapons trafficking, contract murders, extortion, drug trafficking, and prostitution on an international scale."

The FBI's Ten Most Wanted Fugitives during the 2000s is a list, maintained for a sixth decade, of the Ten Most Wanted Fugitives of the United States Federal Bureau of Investigation. At any given time, the FBI is actively searching for 12,000 fugitives. During the 2000s, 36 new fugitives were added to the list. By the close of the decade a total of 494 fugitives had been listed on the Top Ten list, of whom 463 have been captured or located.