A British national extradited to the US last month has pleaded guilty in New York to a role in one of the biggest hacks in social-media history.
More than 130 accounts, including those of leading politicians Barack Obama and Joe Biden, were affected by the Twitter hack nearly three years ago.
An estimated 350million Twitter users saw suspicious tweets from official accounts of the platform's biggest users.
Joseph James O'Connor, 23, known as PlugwalkJoe, pleaded guilty to hacking charges carrying a total maximum sentence of over 70 years in prison.
The hacking was part of a large-scale Bitcoin scam.
O'Connor, who was extradited from Spain, hijacked numerous Twitter accounts and sent out tweets asking followers to send Bitcoin to an account, promising to double their money.
Charged
O'Connor was charged alongside three other men over the scam.
US Assistant Attorney-General Kenneth Polite Jr described in a statement O'Connor's actions as "flagrant and malicious". saying he had "harassed, threatened, and extorted his victims, causing substantial emotional harm".
"Like many criminal actors, O'Connor tried to stay anonymous by using a computer to hide behind stealth accounts and aliases from outside the United States. But this plea shows that our investigators and prosecutors will identify, locate, and bring to justice such criminals to ensure they face the consequences for their crimes."
Cyber experts agreed that the consequences of the Twitter hack could have been far worse if O'Connor and other hackers had had plans more sophisticated than a get-rich-quick scheme.
Disinformation could have been spread to affect political discourse and markets could have been moved by well-worded fake business announcements for example.
The BBC says the hack showed how fragile Twitter's security was at the time, as the hackers managed to use social engineering tricks more akin to those of conmen than of high-level cyber criminals to get access to the powerful internal control panel at the site.
It was, and still is, a hugely embarrassing moment in Twitter's troubled history.