evidence: US regulators and representatives of Elon Musk have remained tight-lipped over whether the billionaire attended an interview on Thursday about his takeover of Twitter - now called X, as required by a federal court. [...] However, Mr Musk fell unusually quiet on X not posting for several hours on Thursday morning, and on Friday wrote a post indicating he had visited Los Angeles. [...] The nation's top securities regulator had called for possible sanctions, if Mr Musk failed to attend.