A South London teenager suspected of having links to cyber activism groups Anonymous and LulzSec was arrested on Tuesday as part of a global sting, police have confirmed.
Scotland Yard's specialist e-crime unit made the arrest under the Computer Misuse Act yesterday and a 16-year-old is in custody, police said.
His identity has not been revealed but sources within Anonymous told The Independent that they believe he could be a former member who was ejected from the group after trying to out fellow members.
Administrators on the group's chatroom were yesterday warning members to be vigilant in the wake of the raids.
A "global" message, sent to all members told them: "We strongly advise you to not use LOIC (Low-orbit Ion Cannon, a tool used by the group to carry out attacks) ever again. In addition to that, keep your ego in check when you hit stuff. Use the anon flag instead of your nickname by which you can be linked to attacks..." [sic]
The raids, carried out in the UK, the USA and the Netherlands, were linked to the attack on PayPal in December last year, as well as other attacks. PayPal was allegedly targeted after the payment service stopped processing donations to WikiLeaks.
In all, 21 suspected "hacktivists" were arrested across the three countries while US police officers secured 35 search warrants related to the inquiry.
Four hackers were arrested by the Dutch National Police Agency, all for alleged cybercrimes, while court documents confirm 14 alleged hackers charged in connection with the PayPal attack were arrested in various US states and are aged between 20 and 42. Two arrests were also made in the US unrelated to the PayPal attack.
In one case, filed in New Jersey, Lance Moore, 21, was accused of exceeding his authorised access AT&T's servers and stealing confidential business information, which was posted on a public file sharing site.
According to The Associated Press, Scott Arciszewski, 21, was arrested on charges of intentional damage to a protected computer, in relation to an attack on the FBI-affiliated Infragard website last month.
A lawyer for one of the PayPal accused compared the acts allegedly committed by his client and the others to civil disobedience. He said: "In the 18th century, people stood on street corners handing out pamphlets saying, 'Beware the all-powerful military and big government'. Some people listened. Some people walked away. Today, pamphleteers use the internet."
Anonymous members said yesterday afternoon that they believed those arrested in the US had been released and had been banned from accessing the internet until they reappear in court.
The US Department of Justice could not immediately confirm the ban but a spokesman said the terms "would not be unusual".