London's Metropolitan police arrested a 16-year-old boy Tuesday in connection with the TalkTalk cyberattack. He has been released until next March after posting bail, according to Mashable.

The arrest is the fourth for the cyberattack, as three others were rounded up beginning Oct. 26 for suspected violation of U.K.'s Computer Misuse Act. Two of them were also teens, ages 16 and 15.

TalkTalk, which provides telephone, Internet and pay TV services, reported a significant and sustained cyberattack in Oct. 21, which possibly compromised private data of its 4 million users. Authorities were called to investigate after the company received a ransom note in connection with the data breach.

So far, TalkTalk confirmed that 1.2 million email addresses, names and addresses have been compromised, BBC News reported. At least 21,000 unique bank account numbers and sort codes as well as 28,000 credit and debit card details were also exposed to the attack.

TalkTalk has since assured its customers that the accessed personal and financial details were not enough to withdraw money or be used in financial transactions. "In addition, we have shared the affected bank details with the major UK banks so they can take their usual actions to protect customers' accounts in the highly unlikely event that a criminal attempts to defraud them," the company said in a statement.