Tesla is under investigation by the US Department of Justice over public statements made by the company and its Chief Executive Elon Musk.
This is according to reports from Bloomberg, citing two people familiar with the matter.
Tesla did not immediately respond to a request for comment; the Department declined to comment.
Federal prosecutors opened a fraud investigation over Musk's tweets in early August that he was contemplating taking Tesla private and had "funding secured" for the deal, the report said.
Musk announced to investors last month, through Twitter, that he wanted to take the electric car company private in a buyout valued at $72 billion, before backing off.
The billionaire' s behavior has raised concerns about his corporate leadership, with several Wall Street analysts and some investors urging Tesla to appoint a strong second-in-command.
Musk has admitted to severe stress from running Tesla.
The US Securities and Exchange Commission has already opened an inquiry into Musk's tweets.
Shares of the company fell in afternoon trade.
