The criminal investigation is also operating alongside a probe by the SEC relating to Musk's tweets about taking the electric-car manufacturer private - an idea which Musk has now walked back following doubts over whether he really did have "funding secured" as he claimed.
The Department of Justice is now investigating Musk's statements, Bloomberg reported, citing anonymous sources. Tesla's stock price rose after Musk's comments, but has since dropped again. Late last month, after the company's board of directors initially backed Musk's claim that the automaker could purchase back shares from investors for $420 each, Tesla ditched its bid to go private.
Goldman Sachs and Silver Lake did not immediately respond to a request for comment.
In its investigation of the company, the S.E.C. sent subpoenas to financial institutions that Tesla hired as it considered going private, according to The New York Times.
Tesla CEO and founder of the Boring Company Elon Musk speaks at a news conference in Chicago.
Some of the delays, Musk admits, are directly due to supply chain issues at Tesla's end, and that the EV maker will concentrate on improving this as soon as Model 3 delivery logistics are ironed out. According to Bloomberg, the "criminal probe" is in its early stages in the USA attorney's office in the Northern District of California.
In an emailed statement, Tesla admits that the Justice Department has asked them for documents and that the company is cooperating. "Given the feedback I've received, it's apparent that most of Tesla's existing shareholders believe we are better off as a public company", he wrote on August 24.
It's unclear whether the criminal investigation is that broad.
Tesla has had to deal with significant turnover in its executive ranks, including this month's controversial departure of its chief accounting officer.
Musk's known hatred toward short sellers should help the government show his wrong intent, said Professor Eric Gordon of the Ross School of Business at the University of MI.
"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.