The teen linked by international law enforcement to anarchist hacking group LulzSec told family he was spending his days and nights locked in his room gaming, not hacking, the Mirror reports.
Ryan Cleary, 19, was arrested earlier this week in connection with a string of attacks on websites around the world. The arrest was the result of a joint investigation by Scotland Yard and the FBI.
Speaking to British press this week, Cleary's mother and brother say they can't believe the teen was a member of hacking group LulzSec, which has claimed responsibility for online attacks of the CIA, PBS, Nintendo and Sony.
Mother Rita Cleary, 44, said her son "lives his life online".
"I thought he was playing computer games in his room," she told the Mirror. "I can't believe it. He rarely left the house.
"I asked him what he was doing and he said he was playing games. Maybe I was naive to believe him."
Investigators told the Mirror that searches of his home and computer led to a "significant amount of material" and that he now faces extradition to the US.
Cleary was remanded to police custody in London today, while not yet entering any plea to the five charges he faces. The teen's attorney says he is assisting police with their investigation into Lulzsec.