In a rare email to a media outlet, Musk applauded the US Department of Justice and snubbed the US Securities and Exchange Commission.

In an email to CNBC, Musk said that he was encouraged by the Justice Department investigating short sellers. This is something the SEC should have done.

Dozens of short sellers have been caught up in a Justice Department probe into their practices and whether they plotted to drive down stock prices by sharing critical research reports before their wider publication. The two short sellers caught up in the inquiry are Andrew Left and Carson Block.

The SEC and Musk have had a rocky relationship, with the SEC probing Musk for his use of social media. The SEC pushed back after Musk accused the agency of harassment.

Musk, who is known for avoiding the media and sharing information on his social media accounts, did not respond to Insider's request for comment. The SEC and Justice Department didn't say anything.

In his email to CNBC, the CEO of the electric car maker lashed out at hedge funds that take advantage of small investors.

They will short a company, conduct a negative publicity campaign to drive the stock price down temporarily and cash out, then do it all over again many times, according to the email.

His comments are similar to the one he wrote when he questioned short-seller practices and called it a scam.

Tech and high-growth stocks have been hit the hardest by the broader market slump.