The suspects flooded online betting sites with false requests for information in so-called "denial of service" attacks. They would then send e-mails demanding money for stopping the attacks, said Yevgeny Yakimovich, the chief of the Russian Interior Ministry's Department K for fighting cyber-crimes.
Yakimovich said the gang had caused over $70 million in damages to British bookmakers. "Their goal was to paralyze a company's work," he told a news conference. British police announced the breakup of the extortion ring last week.
Most victims declined to report the threats to the police, fearing bad publicity, Yakimovich said.
Valery Syzrantsev, the head of the Interior Ministry's Chief Investigating Department, said the hackers targeted nine betting companies, attacking each of them between three to five times and extorting between $5,000 to $50,000.
"Two companies, which suffered especially big losses, agreed to pay $40,000 each," Syzrantsev said. He refused to say how the payments were made and he declined to name the companies.
Bookmaker companies were the most convenient prey because the attacks could be timed to major sport events, Syzrantsev said.
"This case was so significant for Britain and it inflicted such damage that it reached (the) prime minister's desk," Yakimovich said.
British and Russian cyber-detectives tracked down the attacks to several Russian cities and Russian police last week arrested two suspects and seized computers and software in Moscow, St. Petersburg and the Volga River's Saratov region.
Two suspects remained in custody and investigators were working to track down other members of the group, Syzrantsev said.
The suspects could face up to 15 years in prison if convicted of extortion, he said.
In a statement released to the media Wednesday, the Interior Ministry said that the ring also had launched attacks on unidentified British banks, but Yakimovich and Syzrantsev refused to comment on the reports. The ministry also said the gang included residents of other nations. Yakimovich said that several suspects had been briefly detained in Latvia last November, but wouldn't elaborate.
Syzrantsev said the ring consisted of well-educated people in their early 20s who had found each other on the Internet and agreed to work together in the extortion. "There was no chief organizer in plain terms, each of them did his bit of work," he said. "And they didn't consider themselves criminals."