The Department of Justice is investigating Tesla and its CEO Elon Musk for fraud, after Musk tweeted last month that he had "funding secured" for a possible buyout of the company at $420 per share, reports Bloomberg.

The big picture: Tesla already is under civil investigation by the SEC for the same tweet.

Expand chart

A statement from Tesla:

"Last month, following Elon's announcement that he was considering taking the company private, Tesla received a voluntary request for documents from the DOJ and has been cooperative in responding to it. We have not received a subpoena, a request for testimony, or any other formal process. We respect the DOJ's desire to get information about this and believe that the matter should be quickly resolved as they review the information they have received."

Go deeper: Tesla faces threats from every direction.