British police said on Wednesday they had charged a teenager with launching a series of cyber attacks against a national law enforcement agency and two well-known British music industry bodies.
Ryan Cleary, 19, was earlier held as part of a joint investigation with the U.S. FBI into recent attacks on high profile websites.
London's Metropolitan Police said in a statement that Cleary is accused of attacking the website of Britain's Serious Organized Crime Agency (SOCA).
He has also been charged with carrying out attacks against websites owned by the British Phonographic Industry and the International Federation of the Phonographic Industry, police added.
Cleary, of Wickford, a quiet suburban town to the northeast of London, is due to appear in a London court on Thursday charged with five offences under the Criminal Law Act and Computer Misuse Act.
The detached house where he lives had all the curtains drawn and a sign on the door reading: To all concerned, please do not knock for an interview as I'm unable to comment.
Metropolitan Police Commissioner Paul Stephenson described his arrest in the global hunt for a group suspected of targeting companies and police forces as very significant. He did not elaborate.
However, an undercover group that claims responsibility for attacks on the U.S. Central Intelligence Agency (CIA), Britain's SOCA and Sony Corp rejected suggestions that the teenager was a leading figure.
The Lulz Security (LulzSec) group of hackers, which says it has hacked into the websites of the CIA, SOCA and Sony, distanced themselves from Cleary and dismissed any suggestion he was the group's mastermind.
Clearly the UK police are so desperate to catch us that they've gone and arrested someone who is, at best, mildly associated with us. Lame, the group said on its Twitter website.
Ryan Cleary is not part of LulzSec; we house one of our many legitimate chatrooms on his IRC server, but that's it.
Members of LulzSec, which often uses so-called denial-of-service attacks to overwhelm websites with internet traffic, are believed to be scattered around the world collaborating via secret chatrooms.
Security experts say the group emerged from Anonymous, a hacker activist group which became well-known for targeting companies and institutions that opposed WikiLeaks and its founder Julian Assange.
Hackers have also targeted the International Monetary Fund, Lockheed Martin Corp, Citigroup Inc, and Google in recent serious security breaches although no group has claimed responsibility for those attacks.
(Additional reporting by Stefano Ambrogi, Michael Holden and William Maclean; Editing by Jodie Ginsberg, Philippa Fletcher and David Stamp)