Twitter in data-protection probe after '400 million' user details up for sale- PublishedA watchdog is to investigate Twitter after a hacker claimed to have private details linked to more than 400 million accounts.Chief executive Elon Musk did not reply to a tweeted request for comment from leading cyber-security reporter Brian Krebs - though the breach, as Mr Krebs notes, probably occurred before the Tesla boss took over.While acknowledging the amount of data taken had not been verified, the firm's chief technology officer, Alon Gal, told the BBC a number of clues appeared to support the hacker's claim.Only 60 emails out of the sample of 1,000 provided by the hacker in the earlier incident appeared, "so we are confident that this breach is different and significantly bigger", he said.In the online post offering to sell the data, it warns Twitter that its best chance of avoiding a large data-protection fine is to buy back the data "exclusively"."