The Federal Bureau of Investigation is reportedly leading a federal probe into the Twitter (TWTR) - Get Report hacking, which forced the microblogging website to suspend potentially thousands of high-profile accounts.
Shares of the San Francisco company at last check were down 1.1% to $35.29.
Reuters reported that the FBI was heading up the probe, citing confidential sources.
Twitter said hackers used the system access privileges of company employees to gain control of some verified platform accounts - including those of presidential candidate Joe Biden, tech giant Apple (AAPL) - Get Report, and Tesla (TSLA) - Get Report Founder Elon Musk - before seeking payments via a bitcoin account that would be returned in cash.
Around $110,000 of payments were ultimately made, according to blockchain ledgers, before Twitter was able to gain control of the platform and suspend access to the "blue tick," or Twitter-verified, accounts.
A spokesman for the Biden campaign said that Twitter had removed the tweet promoting the scam and locked down Biden’s account.
Earlier in the day, the U.S. Senate Intelligence Committee called on Twitter to inform it in detail about the attack and asked the FBI to probe the incident.
Twitter said in a statement that the company detected what it believed to be "a coordinated social engineering attack by people who successfully targeted some of our employees with access to internal systems and tools."
"We're looking into what other malicious activity they may have conducted or information they may have accessed and will share more here as we have it," the company tweeted.
Sen. Ed Markey (D-Massachusetts) said in a statement Thursday that “Twitter must fully disclose what happened and what it is doing to ensure this never happens again.”