A second arrest has been made by the Metropolitan Police in connection with the cyber attack on the TalkTalk website last week.
The 16-year-old was arrested and held on suspicion of Computer Misuse Act offences after detectives searched a home in Feltham, west London. He has subsequently been bailed, Scotland Yard said.
This latest arrest comes after a 15-year-old boy from County Antrim in Northern Ireland was questioned on Monday in connection with the alleged data theft. He was bailed until a date in November.
The investigation is being carried out by the Metropolitan Police's cyber crime unit, the Police Service of Northern Ireland's cyber crime centre and the National Crime Agency.
Police confirmed officers also carried out a search at a residential property in Liverpool as part of the investigation into the cyber attack.
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