An 18-year-old who became the fifth person to be arrested in connection with an alleged data theft from TalkTalk has been released on bail.
The man from Llanelli was arrested on suspicion of blackmail and has been bailed to a date in March 2016.
The telecoms provider’s website was hit by a hacking attack in October.
Police have arrested and bailed four others, including a 15-year-old boy from County Antrim and two 16-year-olds from London and Norwich.
A 20-year-old man, from Staffordshire, has also been arrested and bailed. All four were arrested on suspicion of Computer Misuse Act offences.
The Metropolitan Police Service’s Cyber Crime Unit (MPCCU) is leading the investigation.
The latest arrest and property search was carried out in conjunction with officers from the Southern Wales Regional Organised Crime Unit.
In the most recent update given by TalkTalk on last month’s cyber attack, the firm said hackers had accessed personal details of almost 157,000 customers, including more than 15,000 bank account numbers and sort codes.
The phone and broadband provider, which has more than four million UK customers, said this was fewer than had been thought originally.
It also said any stolen credit or debit card details were incomplete – and therefore could not be used for financial transactions – but advised customers to remain vigilant against fraud.