San Francisco: Tesla CEO Elon Musk, via his attorney, accused the US Securities and Exchange Commission (SEC) of leaking information about a federal investigation in retaliation for his public criticism of federal financial regulators, a media report said. In a letter on Monday to US District Judge Alison Nathan, Musk's attorney Alex Spiro wrote that "it has become clearer and clearer that the Commission is out to retaliate against my clients for exercising their First Amendment rights -- most recently by criticising the Commission on the public docket and by petitioning this Court for relief", reports CNBC. The letter comes four days after Musk initially alleged that the SEC was engaged in harassment by continually investigating him, that the agency was trying to chill his right to free speech, and had neglected their duties to remit $40 million to shareholders that Tesla and Musk previously paid in fines to settle securities fraud charges. Spiro did not specify which investigation or what type of information may have been leaked by the SEC, and to whom, the report said. In the letter, he alleged that at least one member of the SEC had leaked "certain information regarding its investigation" without providing any supporting evidence. Spiro could not be immediately reached for comment. The SEC did not immediately respond for comments. Also ReadStreaming services are nightmare, says Elon Musk The conflict between Musk and the SEC began in September 2018 when the SEC charged Musk with making "false and misleading" statements to investors after he wrote on Twitter that August that he had secured enough funding for a massive private buyout of Tesla at $420 a share. The stock seesawed all month and the deal Musk alluded to never materialised. Musk and Tesla had to pay $20 million in fines each, and Musk was forced to step down as Chairman for at least three years as part of a revised settlement agreement the agency reached with the automaker and CEO in 2019, the report said. Tesla also had to put in place a system for monitoring Musk's statements to the public about the company -- whether on Twitter, in a blog post or any other medium. The SEC's Steven Buchholz replied to the earlier allegations on Friday, saying the agency was making progress on the task of disbursing the $40 million to shareholders.