Elon Musk and Tesla have escalated their war of words with US regulators, accusing them of an "endless investigation" to curb the tycoon's right to free speech.
The allegations surfaced in a lawyer's letter to US District Judge Alison Nathan, who presided over a 2018 Securities and Exchange Commission (SEC) settlement stemming from Musk's tweet about a potential buyout of Tesla.
Alex Spiro wrote: "The SEC seems to be targeting Mr Musk and Tesla for unrelenting investigation largely because Mr Musk remains an outspoken critic of the government; the SEC's outsized efforts seem calculated to chill his exercise of First Amendment rights."
The letter was written against a backdrop of legal trouble for Tesla.
It disclosed earlier this month that it had received a subpoena from the SEC about its compliance with the 2018 settlement.
Then, Musk was found to have trouble with market rules when he twitched that he had "funding secured" to clearly take his electric car company private at $420 per share.
As a matter of fact, an emancipation was not close.
Tesla and Musk settled by arranging to each remunerate $20m in forfeitures and to let Tesla lawyer probe some of Musk's communications in advance, including twirps that could affect Tesla's stock price.
pMusk also ceded Tesla's chairmanship.
The latest was issued late last year after Musk interviewed his Twitter followers on whether he should give up 10% of his Tesla stake, giving rise to a sell out.
The lawyer's letter on behalf of Musk and Tesla was registered eight days after California's department of fair employment and housing petitioned Tesla over assertions by black workers that it condoned racialism at its Fremont, California, plant.
Tesla, which recounts that legal case as "misguided", is also trying to belittle or badmouth a $137m jury compensation to a blacker erstwhile elevator operator who was purportedly subjected to an adverse work environment at the factory.
While another body, the National Highway Traffic Safety Administration, said on Thursday that it had opened an investigation into Tesla Model 3 and Model Y vehicles after receiving complaints about unexpected braking tied to its Autopilot system.