Tesla Inc and its Chief Executive Elon Musk are under criminal investigation by the US Department of Justice over public statements about taking the electric carmaker private, it was reported on Tuesday. Tesla did not immediately respond to a request for comment, while DoJ declined to comment. Federal prosecutors opened a fraud investigation, the report said, citing two people familiar with the matter, over Musk's tweets in early August that he had secured funding for a buyout deal valued at $72 billion, before backing off. Musk has already been sued by short-sellers such as Citron Research and is facing a probe by the US Securities and Exchange Commission. The billionaire CEO's behaviour has raised concerns about his leadership, with several Wall Street analysts and some investors urging Tesla to appoint a strong second-in-command.