British police arrested a teenager believed to be a leader of computer hacking groups that boasted attacks on the networks of the CIA, Sony and Rupert Murdoch's media empire.

The arrest of the 19-year-old man, who UK police said goes by the hacker nickname Topiary, may be the most significant to date in a global effort to end a cyber-crime spree by the hacker activist groups Lulz Security and Anonymous.

Topiary is believed to have controlled the main Twitter account of Lulz Security, which the group used to publish data obtained by hacking into corporate and government networks. The messages were written in an irreverent style, filled with sarcasm, expletives and inside jokes that were sometimes difficult to decipher.

The arrest was part of a pre-planned, intelligence-led operation, the police service said.

The arrest of 'Topiary' is important as it sends a strong message to other hackers or would-be hackers, said Chet Wisniewski, a security researcher with UK anti-virus software maker Sophos.

While many have found the antics of Lulz Security entertaining, breaking into computers and stealing the personal details of innocent people is a serious crime, he said.

British police said the suspect was being held at a house in the remote Shetland Islands, off Scotland's northeast coast, though they planned to take him to a police station in central London.

LulzSec has claimed responsibility for cyber-attacks on the U.S. Central Intelligence Agency, multiple Sony Corp websites and the website of Murdoch's British newspaper group, News International.

The group has attracted widespread global media coverage for its stunts and has nearly 350,000 followers on Twitter, the messaging website.

Last month, British police charged Ryan Cleary, 19, with attacking the website of Britain's Serious Organized Crime Agency (SOCA) and sites owned by the British Phonographic Industry and the International Federation of the Phonographic Industry.

Cleary, arrested as part of a joint investigation by London police and the U.S. FBI into recent attacks on high-profile websites, was given bail.

The FBI raided six locations in New York earlier this month and conducted searches in California as part of an investigation into the hacking group Anonymous.

The groups issued a statement on Wednesday, saying that the FBI had wrongfully arrested some of their supporters for participating in digital sit-ins. Those campaigns had temporarily shut down the websites of targeted groups by overwhelming them with Internet traffic.

Anonymous 'suspects' may face a fine of up to $500,000, with the addition of 15 years' jail time, all for taking part in a historical activist movement, the statement said.

The statement also urged supporters to boycott eBay Inc's PayPal electronic payment service. It asked supporters to close their PayPal accounts.

The hacker activists have previously attacked PayPal to show their opposition to the service's refusal to process payments to WikiLeaks, the website founded by Julian Assange that published copies of secret U.S. government diplomatic cables.

A spokesman for PayPal said the company had observed no changes in normal operations, including the number of accounts that had been closed overnight.

Anonymous also claimed to have broken into Apple Inc servers in July. It also launched attacks in December that temporarily shut down sites of MasterCard Inc and Visa Inc using simple software available on the Internet.

(Reporting by Peter Griffiths in London; Additional reporting by Jim Finkle in Boston and Alistair Barr in San Francisco; Editing by Steve Orlofsky)

Hacking