Elon Musk has denied a Wall Street Journal report that claimed he had an affair with Nicole Shanahan, the wife of the Google co-founder Sergey Brin, accusing the news outlet of running “hit pieces” on him and Tesla. The chief executive of the electric carmaker tweeted on Monday rejecting the affair claim as “total BS”, adding that he and Brin were still friends. Citing unidentified sources, the Wall Street Journal reported at the weekend that Musk had engaged in a brief affair with Shanahan in December last year. The paper claimed the affair had prompted Brin to file for divorce from Shanahan in January and had ended the tech billionaires’ long friendship. Musk tweeted that he was at a party with Brin on Sunday and that there was “nothing romantic” between him and Shanahan, a lawyer and research fellow at CodeX, an organisation dedicated to using technology to improve legal processes based at Stanford University in California. She is also the president of a foundation that focuses on criminal justice reform, reproductive longevity for women and climate science. In a later tweet to his more than 100 million followers, Musk said he had “lost count” of the number of “hit pieces” about him published by the Wall Street Journal. Musk claimed the news organisation had once reported that the FBI was about to arrest him, although a 2018 WSJ article alleging a criminal investigation into Tesla does not refer to arrests being planned. In a subsequent tweet, Musk said the paper should run stories that “actually matter to their readers and have solid factual basis”. Brin filed for divorce citing “irreconcilable differences”, the Journal said, quoting records it said were filed in Santa Clara County superior court. Brin is a board member at Google’s parent company, Alphabet, and is the world’s eighth richest person, with a fortune worth $94.6bn (£78.6bn), according to Bloomberg. Musk is the world’s richest person and is worth $242bn. In its report, the Journal also said Brin instructed his advisers to sell personal investments in Musk’s companies after he came to know about the affair. The paper said it was not able to determine how large those investments were, nor whether any sales were made. A spokeswoman for the Wall Street Journal said: “We are confident in our sourcing, and we stand by our reporting.” Google and Shanahan have been contacted for comment. The Journal’s allegation was published as Musk faces a court battle in October over his attempts to terminate his $44bn purchase of Twitter. The social media platform wants to force Musk to go ahead with an agreed transaction that values the company at $54.20 per share. Musk walked away from the deal this month, citing concerns over the number of bot accounts active on Twitter. Meanwhile, Tesla disclosed in a regulatory filing on Monday that it had received a second subpoena from the US financial watchdog in relation to Musk’s tweets in 2018 about taking the company private. The company said it had received the subpoena from the US Securities and Exchange Commission (SEC) on 13 June and that it would cooperate. In November last year, the regulator subpoenaed Tesla in relation to a settlement that required Musk’s tweets on material information to be vetted. In 2018, Musk settled an SEC lawsuit over his tweets about taking Tesla private by agreeing to let the company’s lawyers pre-approve tweets that contained material information about Tesla.