Authorities in London have arrested - and released - a second teenager linked to the recent hack of wireless and broadband provider TalkTalk.

Detectives from the Metropolitan Police Cyber Crime Unit arrested a 16-year-old boy at his home in Feltham, London, on Thursday on suspicion of violating the country's Computer Misuse Act. His residence - along with a second home in Liverpool - was searched, police said, adding that he has since been released on bail.

Earlier this week, a 15-year-old teen from County Antrim, Northern Ireland, was taken into custody on suspicion of the same offense. He, too, has since been released on bail. Authorities said he is due back in court sometime in November. A court date for the 16-year-old hasn't been set.

TalkTalk said earlier today that the extent of the data accessed in the attack is significantly less than originally suspected.

The telecom confirmed that less than 21,000 unique bank account numbers and sort codes were accessed and that fewer than 28,000 obscured credit and debit card details were obtained. Furthermore, less than 15,000 customer dates of birth were exposed while less than 1.2 million customer e-mail addresses, names and phone numbers were compromised.

As the company previously stated, any card details that were compromised can't be used for financial transactions as the middle six digits are missing.

It was initially reported that as many as four million customers were impacted by the breach.

The Metropolitan Police said the investigation is ongoing.