Bloomberg reported on a statement from Tesla saying they received "a voluntary request for documents from the DOJ and has been cooperative in responding to it". The announcement raised the stock price 11 per cent in one day, but it has since fallen. Nearly a week later, Musk said the basis for his statement was conversations with Saudi Arabia's Public Investment Fund, which first expressed interest in helping take the company private in early 2017.
As of writing, Tesla stock is trading down 5.88% at $277.98 per share.
A British diver who helped rescue boys trapped in a Thai cave is suing Elon Musk for $57,000 (£43,300) after the Tesla chief called him a paedophile. The news comes on top of prior reports of a civil probe by the Securities and Exchange Commission. Tesla's shares dropped over 7% on the news.
A spokeswoman for the Justice Department declined to comment on the report.
The lawsuit filed in the Los Angeles federal court on Monday seeks more than $75,000 in damages and a court order stopping Musk from making further allegations.
The Justice Department generally does not confirm or deny investigations, spokeswoman Nicole Navas Oxman in Washington said.
Once it has solved its "insane vehicle delivery logistics", Musk said, Tesla would concentrate on launching more service centers to improve the pace of repairs and bringing collision repairs in-house.
The DoJ investigation deals with the USA attorney's office in the Northern California district.
Elon Musk "speaks loosely", but his conduct probably doesn't rise to the criminal level.
Word that McAnear was heading for the off-ramp followed chief accounting officer Dave Morton's departure after just a month on the job, citing the company's frenetic pace. Prosecutors would have to make the case that Musk lied to influence the stock price, he said.
"That's not what anyone in the financial markets thinks of when you say 'funding secured, '" said Stephen Diamond, an expert on securities law at Santa Clara University, in an interview with Ars last month.