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.
Now Tesla is under additional, and perhaps more intense scrutiny, this time coming not from the SEC, but the Department of Justice, according to a report from Bloomberg published on September 18th.
A Tesla spokesperson said last month the DOJ requested documents in a "voluntary request" and Tesla has "been cooperative in responding to it". Shares in the company soared after Musk said on Twitter that he had "funding secured" to go private.
As of writing, Tesla stock is trading down 5.88% at $277.98 per share.
In a series of tweets in July, Tesla CEO and SpaceX founder Elon Musk referred to a cave diver involved in the rescue of a Thai soccer team as a "pedo guy". Bloomberg reported earlier that federal prosecutors had opened a criminal fraud investigation.
Tesla's shares were sent skidding lower by the announcement but have since rebounded slightly.
The stock shot up after the announcement but has declined substantially since then.
"Tesla is bringing most collision repairs in-house, as outside firms take weeks to months for repairs, driving Tesla owners (and us) insane", he said.
The involvement of the Justice Department would be significant because the Securities and Exchange Commission-which has been investigating the case for several weeks-only has the power to bring civil charges.
CNN has reached out for comment to the United States attorney's office in San Francisco, which is leading the probe, according to the Bloomberg report. Tesla has recently transitioned from "production hell" to "delivery logistics hell," according to a tweet from Musk (dude, stop tweeting).
His first tweet revealing the paradigm shift sympathizes with his customers, and the following statement in the thread commented on how the new Tesla mentality is being put into action already with repairs being completed in under 24 hours rather than over months.
But SEC enforcement actions are nearly always civil matters, resulting in fines or other sanctions, up to banning up an executive from serving as an officer of a public company.
The company has been ramping up production of its Model 3 electric auto, to such an extent that delivery issues are starting to pop up.