While some initially thought the hack was the work of professionals, it turns out the “mastermind” of one of the most high-profile hacks in recent years was a 17-year-old recent high school graduate from Florida, the authorities said on Friday.
Graham Ivan Clark was arrested in his Tampa apartment, where he lived by himself, early Friday, state officials said. He faces 30 felony charges in the hack, including fraud, and is being charged as an adult.
Two other people, Mason John Sheppard, 19, of the United Kingdom, and Nima Fazeli, 22, of Orlando, Fla., were accused of helping Mr. Clark during the takeover. Prosecutors said the two appeared to have aided the central figure in the attack, who went by the name Kirk. Documents released on Friday do not provide the real identity of Kirk, but they suggest that it was Mr. Clark.
Mr. Clark was skilled enough to go unnoticed inside Twitter’s network, said Andrew Warren, the Florida state attorney handling the case.
“This was not an ordinary 17-year-old,” Mr. Warren said.
Mr. Clark convinced one of the company’s employees that he was a co-worker in the technology department who needed the employee’s credentials to access the customer service portal, a criminal affidavit from Florida said. By the time the hackers were done, they had broken into 130 accounts and raised significant new questions about Twitter’s security.
Despite the hackers’ cleverness, their plan quickly fell apart, according to court documents. They left hints about their real identities and scrambled to hide the money they’d made once the hack became public. Their mistakes allowed law enforcement to quickly track them down.
Federal authorities were already tracking Mr. Clark’s online activity before the Twitter hack, according to legal documents. In April, the Secret Service seized over $700,000 worth of Bitcoin from him, but it was unclear why.