Shares in Tesla plummeted six percent after the US government launched an investigation into the group.

The Department of Justice is investigating Elon Musk’s tweet that said he had “funding secured” to take his company private once shares hit $420.

A Tesla spokesperson said in a statement: “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.”

Following Musk’s tweet about taking Tesla private, shares in the electric car maker as much as 11 percent and the company’s value surged $1.2 billion.

The carmaker later backtracked and released a statement saying that a decision had not yet been made.

Musk’s comments also led to shareholder lawsuits, claiming that Musk was attempting to manipulate the stock price of Tesla.

Soon after Bloomberg reported the news of the Department of Justice’s investigation, shares in Tesla fell six percent before rebounding later in the afternoon.

This is the latest scandal for Musk. He was recently sued by the British diver who led the rescue of 12 Thai boys from a flooded cave after Musk repeatedly called him a paedophile.

Lin Wood, a US lawyer acting for the British diver, said: “Elon Musk falsely accused Vern Unsworth of being guilty of heinous crimes. Musk’s influence and wealth cannot convert his lies into truth or protect him from accountability for his wrongdoing in a court of law.”

Shares in Tesla (NASDAQ: TSLA) are currently trading down 3.35 percent at 284,96 (0808GMT).