London (CNN) -- The computer hacking collective LulzSec denied that a teenager arrested this week was a key player in the group, and claimed Wednesday it brought down the Brazilian government's website.
"TANGO DOWN," the group announced on Twitter, using military slang that has been appropriated by hackers to say they have interrupted service to a website. The websites of the Brazilian government and presidency were failing to load Wednesday morning, hours after LulzSec said it attacked them.
It also downplayed the role in LulzSec of Ryan Clearly, whom British media have named as the 19-year-old hacker who was arrested in Essex, outside of London, on Monday.
"Ryan Cleary is not part of LulzSec; we house one of our many legitimate chatrooms on his IRC server, but that's it," the group tweeted. "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 suspect remains in custody but has not yet been charged, London's Metropolitan Police told CNN Wednesday. They did not confirm his identity. Naming suspects who have been arrested is illegal in Britain.
On Tuesday they announced the arrest of a 19-year-old suspected of hacking into systems and mounting denial of service attacks against "a number of international businesses and intelligence agencies."
A police spokesman, who declined to be named in line with custom, said the arrested man's computers will be examined for activities related to hacks against the UK's Serious Organized Crime Agency, the CIA and Sony.
Sony's PlayStation Network went down on April 20 after what Sony said was a massive data breach. It had more than 70 million subscribers at the time.
It began coming back online in mid-May. The PlayStation Store did not reopen until June 2.
The company estimated the cost of that attack will total $171 million.
Hackers later broke into Sony Pictures' website, compromising the accounts of over 1 million users, and the gaming company Sega, stealing nearly 1.3 million users' details via a British subsidiary of the Japanese company. Sega makes games for PlayStation and other gaming systems.
The suspect's computer will also be examined for links to LulzSec, another police spokesman told CNN, who also declined to be named in line with custom.
"This link has not been established yet as it is still early days," the spokesman said.
LulzSec posted an irreverent denial that its leader was the one arrested.
"Seems the glorious leader of LulzSec got arrested, it's all over now ... wait ... we're all still here! Which poor bastard did they take down?" they said on Twitter several hours after the announcement of the arrest.
LulzSec claimed recently to have attacked the CIA website, and took credit for hacking into the website of the American public broadcaster PBS and posting a fake story saying the rapper Tupac Shakur was still alive. He was killed nearly 15 years ago.
It's unclear whether LulzSec members played a role in the Sony PlayStation Network breach.
But they have posted on their website what they claim is proprietary information from Sony Pictures and other Sony properties' websites.
On Friday, on the occasion of their 1,000th tweet, the group posted a manifesto of sorts in which they said people, including their targets and advocates of Internet freedom, should be thankful.
"The main anti-LulzSec argument suggests that ... our actions are causing clowns with pens to write new rules for you," the group wrote. "But what if we just hadn't released anything? What if we were silent? That would mean we would be secretly inside FBI affiliates right now, inside PBS, inside Sony ... watching ... abusing ... ."
They seemed to suggest that by making their attacks public, they'll push websites to increase security. They said they're sitting on account information for 200,000 players of the online game Brink, but moments later said that releasing people's information is worth doing sometimes because it's fun.
"Yes, yes, there's always the argument that releasing everything in full is just as evil, what with accounts being stolen and abused, but welcome to 2011," they wrote. "This is the lulz lizard era, where we do things just because we find it entertaining."
Analysts said the group appears to be some sort of spin-off of "Anonymous," the loose coalition of hackers that grew to prominence through their support of the whistle-blower site WikiLeaks.
But while Anonymous has its own set of moral codes and is largely politically motivated, LulzSec seems to be random.
For every hack like the one on PBS, which the group said came out of anger over a documentary about WikiLeaks, there's the cracking of porn site pron.com -- and a subsequent public list of members' e-mail addresses and passwords.
CNN's Per Nyberg, Carol Jordan and Doug Gross contributed to this report.